101
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Bian M, Zhang Y, Du X, Xu J, Cui J, Gu J, Zhu W, Zhang T, Chen Y. Apigenin-7-diglucuronide protects retinas against bright light-induced photoreceptor degeneration through the inhibition of retinal oxidative stress and inflammation. Brain Res 2017; 1663:141-150. [PMID: 28336272 DOI: 10.1016/j.brainres.2017.03.019] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Revised: 03/10/2017] [Accepted: 03/17/2017] [Indexed: 11/27/2022]
Abstract
Vision impairment in retinal degenerative diseases such as age-related macular degeneration is primarily associated with photoreceptor degeneration, in which oxidative stress and inflammatory responses are mechanistically involved as central players. Therapies with photoreceptor protective properties remain to be developed. Apigenin-7-diglucuronide (A7DG), a flavonoid glycoside, is present in an assortment of medicinal plants with anti-inflammatory or ant-oxidant activities. However, the pharmacological significance of A7DG remains unknown in vivo. The current study isolated A7DG from Glechoma longituba (Nakai) Kuprian and investigated the retinal protective effect A7DG in mice characterized by bright light-induced photoreceptor degeneration. The results showed that A7DG treatment led to remarkable photoreceptor protection in bright light-exposed BALB/c mice. Moreover, A7DG treatment alleviated photoreceptor apoptosis, mitigated oxidative stress, suppressed reactive gliosis and microglial activation and attenuated the expression of proinflammatory genes in bright light-exposed retinas. The results demonstrated for the first time remarkable photoreceptor protective activities of A7DG in vivo. Inhibition of bright light-induced retinal oxidative stress and retinal inflammatory responses was associated with the retinal protection conferred by A7DG. The work here warrants further evaluation of A7DG as a pharmacological candidate for the treatment of vision-threatening retinal degenerative disorders. Moreover, given the general implication of oxidative stress and inflammation in the pathogenesis of neurodegeneration, A7DG could be further tested for the treatment of other neurodegenerative disorders.
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Affiliation(s)
- Minjuan Bian
- Yueyang Hospital and Clinical Research Institute of Integrative Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai 200437, China
| | - Yong Zhang
- Shanghai Institute of Materia Medica Chinese Academy of Sciences, Shanghai 201203, China
| | - Xiaoye Du
- Yueyang Hospital and Clinical Research Institute of Integrative Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai 200437, China
| | - Jing Xu
- East China University of Science and Technology School of Pharmacy, Shanghai 200237, China
| | - Jingang Cui
- Yueyang Hospital and Clinical Research Institute of Integrative Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai 200437, China
| | - Jiangping Gu
- East China University of Science and Technology School of Pharmacy, Shanghai 200237, China
| | - Weiliang Zhu
- Shanghai Institute of Materia Medica Chinese Academy of Sciences, Shanghai 201203, China
| | - Teng Zhang
- Yueyang Hospital and Clinical Research Institute of Integrative Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai 200437, China.
| | - Yu Chen
- Yueyang Hospital and Clinical Research Institute of Integrative Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai 200437, China.
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102
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Lin FL, Lin CH, Ho JD, Yen JL, Chang HM, Chiou GCY, Cheng YW, Hsiao G. The natural retinoprotectant chrysophanol attenuated photoreceptor cell apoptosis in an N-methyl-N-nitrosourea-induced mouse model of retinal degenaration. Sci Rep 2017; 7:41086. [PMID: 28112220 PMCID: PMC5253624 DOI: 10.1038/srep41086] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Accepted: 12/15/2016] [Indexed: 01/27/2023] Open
Abstract
Retinitis pigmentosa (RP) is an inherited photoreceptor-degenerative disease, and neuronal degeneration in RP is exacerbated by glial activation. Cassia seed (Jue-ming-zi) is a traditional herbal medicine commonly used to treat ocular diseases in Asia. In this report, we investigated the retina-protective effect of chrysophanol, an active component of Cassia seed, in an N-methyl-N-nitrosourea (MNU)-induced mouse model of RP. We determined that chrysophanol inhibited the functional and morphological features of MNU-induced retinal degeneration using scotopic electroretinography (ERG), optical coherence tomography (OCT), and immunohistochemistry analysis of R/G opsin and rhodopsin. Furthermore, TUNEL assays revealed that chrysophanol attenuated MNU-induced photoreceptor cell apoptosis and inhibited the expression of the apoptosis-associated proteins PARP, Bax, and caspase-3. In addition, chrysophanol ameliorated reactive gliosis, as demonstrated by a decrease in GFAP immunolabeling, and suppressed the activation of matrix metalloproteinase (MMP)-9-mediated gelatinolysis. In vitro studies indicated that chrysophanol inhibited lipopolysaccharide (LPS)-induced iNOS and COX-2 expression in the BV2 mouse microglia cell line and inhibited MMP-9 activation in primary microglia. Our results demonstrate that chrysophanol provided neuroprotective effects and inhibited glial activation, suggesting that chrysophanol might have therapeutic value for the treatment of human RP and other retinopathies.
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Affiliation(s)
- Fan-Li Lin
- Graduate Institute of Medical Sciences and Department of Pharmacology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Cheng-Hui Lin
- School of Pharmacy, College of Pharmacy, Taipei Medical University, Taipei, Taiwan
| | - Jau-Der Ho
- Department of Ophthalmology, Taipei Medical University Hospital, Taipei, Taiwan
| | - Jing-Lun Yen
- Graduate Institute of Medical Sciences and Department of Pharmacology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Hung-Ming Chang
- Department of Anatomy, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - George C Y Chiou
- Department of Neuroscience and Experimental Therapeutics and Institute of Ocular Pharmacology, College of Medicine, Texas A&M Health Science Center, College Station, TX, USA
| | - Yu-Wen Cheng
- School of Pharmacy, College of Pharmacy, Taipei Medical University, Taipei, Taiwan
| | - George Hsiao
- Graduate Institute of Medical Sciences and Department of Pharmacology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
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103
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Palczewska G, Maeda A, Golczak M, Arai E, Dong Z, Perusek L, Kevany B, Palczewski K. Receptor MER Tyrosine Kinase Proto-oncogene (MERTK) Is Not Required for Transfer of Bis-retinoids to the Retinal Pigmented Epithelium. J Biol Chem 2016; 291:26937-26949. [PMID: 27875314 DOI: 10.1074/jbc.m116.764563] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Revised: 11/14/2016] [Indexed: 01/08/2023] Open
Abstract
Accumulation of bis-retinoids in the retinal pigmented epithelium (RPE) is a hallmark of aging and retinal disorders such as Stargardt disease and age-related macular degeneration. These aberrant fluorescent condensation products, including di-retinoid-pyridinium-ethanolamine (A2E), are thought to be transferred to RPE cells primarily through phagocytosis of the photoreceptor outer segments. However, we observed by two-photon microscopy that mouse retinas incapable of phagocytosis due to a deficiency of the c-Mer proto-oncogene tyrosine kinase (Mertk) nonetheless contained fluorescent retinoid condensation material in their RPE. Primary RPE cells from Mertk-/- mice also accumulated fluorescent products in vitro Finally, quantification of A2E demonstrated the acquisition of retinal condensation products in Mertk-/- mouse RPE prior to retinal degeneration. In these mice, we identified activated microglial cells that likely were recruited to transport A2E-like condensation products to the RPE and dispose of the dying photoreceptor cells. These observations demonstrate a novel transport mechanism between photoreceptor cells and RPE that does not involve canonical Mertk-dependent phagocytosis.
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Affiliation(s)
| | - Akiko Maeda
- the Departments of Ophthalmology and Visual Sciences and
| | - Marcin Golczak
- Pharmacology and Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106
| | - Eisuke Arai
- the Departments of Ophthalmology and Visual Sciences and
| | | | | | - Brian Kevany
- Pharmacology and Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106
| | - Krzysztof Palczewski
- Pharmacology and Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106
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104
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Cho SH, Song JY, Shin J, Kim S. Neonatal disease environment limits the efficacy of retinal transplantation in the LCA8 mouse model. BMC Ophthalmol 2016; 16:193. [PMID: 27809828 PMCID: PMC5095973 DOI: 10.1186/s12886-016-0368-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Accepted: 10/20/2016] [Indexed: 11/17/2022] Open
Abstract
Background Mutations of Crb1 gene cause irreversible and incurable visual impairment in humans. This study aims to use an LCA8-like mouse model to identify host-mediated responses that might interfere with survival, retinal integration and differentiation of grafted cells during neonatal cell therapy. Methods Mixed retinal donor cells (1 ~ 2 × 104) isolated from neural retinas of neonatal eGFP transgenic mice were injected into the subretinal space of LCA8-like model neonatal mice. Markers of specific cell types were used to analyze microglial attraction, CSPG induction and retinal cell differentiation. The positions of host retinal cells were traced according to their laminar location during disease progression to look for host cell rearrangements that might inhibit retinal integration of the transplanted cells. Results Transplanted retinal cells showed poor survival and attracted microglial cells, but CSPG was not greatly induced. Retinas of the LCA8 model hosts underwent significant cellular rearrangement, including rosette formation and apical displacement of inner retinal cells. Conclusions Local disease environment, particularly host immune responses to injected cells and formation of a physical barrier caused by apical migration of host retinal cells upon disruption of outer limiting membrane, may impose two major barriers in LCAs cell transplantation therapy.
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Affiliation(s)
- Seo-Hee Cho
- Department of Anatomy and Cell Biology, Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine at Temple University, 3500 N. Broad Street, Philadelphia, PA, 19140, USA.
| | - Ji Yun Song
- Department of Anatomy and Cell Biology, Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine at Temple University, 3500 N. Broad Street, Philadelphia, PA, 19140, USA
| | - Jinyeon Shin
- Department of Anatomy and Cell Biology, Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine at Temple University, 3500 N. Broad Street, Philadelphia, PA, 19140, USA
| | - Seonhee Kim
- Department of Anatomy and Cell Biology, Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine at Temple University, 3500 N. Broad Street, Philadelphia, PA, 19140, USA
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105
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Li J, Zhang Y, Cai X, Xia Q, Chen J, Liao Y, Liu Z, Wu Y. All-trans-retinal dimer formation alleviates the cytotoxicity of all-trans-retinal in human retinal pigment epithelial cells. Toxicology 2016; 371:41-48. [PMID: 27751755 DOI: 10.1016/j.tox.2016.10.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Accepted: 10/09/2016] [Indexed: 12/20/2022]
Abstract
Effective clearance of all-trans-retinal (atRAL) from retinal pigment epithelial (RPE) cells is important for avoiding its cytotoxicity. However, the metabolism of atRAL in RPE cells is poorly clarified. The present study was designed to analyze metabolic products of atRAL and to compare the cytotoxicity of atRAL versus its derivative all-trans-retinal dimer (atRAL-dimer) in human RPE cells. We found that all-trans-retinol (atROL) and a mixture of atRAL condensation metabolites including atRAL-dimer and A2E were generated after incubating RPE cells with atRAL for 6h, and the amount of atRAL-dimer was significantly higher than that of A2E. In the eyes of Rdh8-/- Abca4-/- mice, a mouse model with defects in retinoid cycle that displays some symbolic characteristics of age-related macular degeneration (AMD), the level of atRAL-dimer was increased compared to wild-type mice, and was even much greater than that of A2E & isomers. The cytotoxicity of atRAL-dimer was reduced compared with its precursor atRAL. The latter could provoke intracellular reactive oxygen species (ROS) overproduction, increase the mRNA expression of several oxidative stress related genes (Nrf2, HO-1, and γ-GCSh), and induce ΔΨm loss in RPE cells. By contrast, the abilities of atRAL-dimer to induce intracellular ROS and oxidative stress were much weaker versus that of concentration-matched atRAL, and atRAL-dimer exhibited no toxic effect on mitochondrial function at higher concentrations. In conclusion, the formation of atRAL-dimer during atRAL metabolic process ameliorates the cytotoxicity of atRAL by reducing oxidative stress.
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Affiliation(s)
- Jie Li
- Fujian Provincial Key Laboratory of Ophthalmology and Visual Science, Eye Institute of Xiamen University, College of Medicine, Xiamen University, Xiamen, Fujian Province, China; Taizhou First People's Hospital, Taizhou, Zhejiang Province, China
| | - Yanli Zhang
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang Province, China
| | - Xianhui Cai
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang Province, China
| | - Qingqing Xia
- Taizhou First People's Hospital, Taizhou, Zhejiang Province, China
| | - Jingmeng Chen
- College of Medicine, Xiamen University, Xiamen, Fujian Province, China
| | - Yi Liao
- Fujian Provincial Key Laboratory of Ophthalmology and Visual Science, Eye Institute of Xiamen University, College of Medicine, Xiamen University, Xiamen, Fujian Province, China
| | - Zuguo Liu
- Fujian Provincial Key Laboratory of Ophthalmology and Visual Science, Eye Institute of Xiamen University, College of Medicine, Xiamen University, Xiamen, Fujian Province, China
| | - Yalin Wu
- Fujian Provincial Key Laboratory of Ophthalmology and Visual Science, Eye Institute of Xiamen University, College of Medicine, Xiamen University, Xiamen, Fujian Province, China.
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106
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Chen Y, Palczewska G, Masuho I, Gao S, Jin H, Dong Z, Gieser L, Brooks MJ, Kiser PD, Kern TS, Martemyanov KA, Swaroop A, Palczewski K. Synergistically acting agonists and antagonists of G protein-coupled receptors prevent photoreceptor cell degeneration. Sci Signal 2016; 9:ra74. [PMID: 27460988 DOI: 10.1126/scisignal.aag0245] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Photoreceptor cell degeneration leads to visual impairment and blindness in several types of retinal disease. However, the discovery of safe and effective therapeutic strategies conferring photoreceptor cell protection remains challenging. Targeting distinct cellular pathways with low doses of different drugs that produce a functionally synergistic effect could provide a strategy for preventing or treating retinal dystrophies. We took a systems pharmacology approach to identify potential combination therapies using a mouse model of light-induced retinal degeneration. We showed that a combination of U.S. Food and Drug Administration-approved drugs that act on different G protein (heterotrimeric guanine nucleotide-binding protein)-coupled receptors (GPCRs) exhibited synergistic activity that protected retinas from light-induced degeneration even when each drug was administered at a low dose. In functional assays, the combined effects of these drugs were stimulation of Gi/o signaling by activating the dopamine receptors D2R and D4R, as well as inhibition of Gs and Gq signaling by antagonizing D1R and the α1A-adrenergic receptor ADRA1A, respectively. Moreover, transcriptome analyses demonstrated that such combined GPCR-targeted treatments preserved patterns of retinal gene expression that were more similar to those of the normal retina than did higher-dose monotherapy. Our study thus supports a systems pharmacology approach to identify treatments for retinopathies, an approach that could extend to other complex disorders.
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Affiliation(s)
- Yu Chen
- Yueyang Hospital and Clinical Research Institute of Integrative Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai 200437, China. Department of Pharmacology, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA.
| | | | - Ikuo Masuho
- Department of Neuroscience, The Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, USA
| | - Songqi Gao
- Department of Pharmacology, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA
| | - Hui Jin
- Department of Pharmacology, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA
| | | | - Linn Gieser
- Neurobiology-Neurodegeneration and Repair Laboratory, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Matthew J Brooks
- Neurobiology-Neurodegeneration and Repair Laboratory, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Philip D Kiser
- Department of Pharmacology, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA. Research Service, Louis Stokes Cleveland VA Medical Center, Cleveland, OH 44106, USA
| | - Timothy S Kern
- Department of Pharmacology, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA. Research Service, Louis Stokes Cleveland VA Medical Center, Cleveland, OH 44106, USA. Department of Medicine, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Kirill A Martemyanov
- Department of Neuroscience, The Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, USA
| | - Anand Swaroop
- Neurobiology-Neurodegeneration and Repair Laboratory, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Krzysztof Palczewski
- Department of Pharmacology, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA. Polgenix Inc., Cleveland, OH 44106, USA.
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107
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Eandi CM, Charles Messance H, Augustin S, Dominguez E, Lavalette S, Forster V, Hu SJ, Siquieros L, Craft CM, Sahel JA, Tadayoni R, Paques M, Guillonneau X, Sennlaub F. Subretinal mononuclear phagocytes induce cone segment loss via IL-1β. eLife 2016; 5. [PMID: 27438413 PMCID: PMC4969036 DOI: 10.7554/elife.16490] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2016] [Accepted: 07/19/2016] [Indexed: 12/19/2022] Open
Abstract
Photo-transduction in cone segments (CS) is crucial for high acuity daytime vision. For ill-defined reasons, CS degenerate in retinitis pigmentosa (RP) and in the transitional zone (TZ) of atrophic zones (AZ), which characterize geographic atrophy (GA). Our experiments confirm the loss of cone segments (CS) in the TZ of patients with GA and show their association with subretinal CD14+mononuclear phagocyte (MP) infiltration that is also reported in RP. Using human and mouse MPs in vitro and inflammation-prone Cx3cr1GFP/GFPmice in vivo, we demonstrate that MP-derived IL-1β leads to severe CS degeneration. Our results strongly suggest that subretinal MP accumulation participates in the observed pathological photoreceptor changes in these diseases. Inhibiting subretinal MP accumulation or Il-1β might protect the CS and help preserve high acuity daytime vision in conditions characterized by subretinal inflammation, such as AMD and RP. DOI:http://dx.doi.org/10.7554/eLife.16490.001
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Affiliation(s)
- Chiara M Eandi
- Sorbonne Universités, UPMC University Paris 06, INSERM, CNRS, Paris, France.,Institut de la Vision, Paris, France.,Department of Clinical Science, University of Torino, Torino, Italy.,Eye Clinic, University of Torino, Torino, Italy
| | - Hugo Charles Messance
- Sorbonne Universités, UPMC University Paris 06, INSERM, CNRS, Paris, France.,Institut de la Vision, Paris, France
| | - Sébastien Augustin
- Sorbonne Universités, UPMC University Paris 06, INSERM, CNRS, Paris, France.,Institut de la Vision, Paris, France
| | - Elisa Dominguez
- Sorbonne Universités, UPMC University Paris 06, INSERM, CNRS, Paris, France.,Institut de la Vision, Paris, France
| | - Sophie Lavalette
- Sorbonne Universités, UPMC University Paris 06, INSERM, CNRS, Paris, France.,Institut de la Vision, Paris, France
| | - Valérie Forster
- Sorbonne Universités, UPMC University Paris 06, INSERM, CNRS, Paris, France.,Institut de la Vision, Paris, France
| | - Shulong Justin Hu
- Sorbonne Universités, UPMC University Paris 06, INSERM, CNRS, Paris, France.,Institut de la Vision, Paris, France
| | - Lourdes Siquieros
- Sorbonne Universités, UPMC University Paris 06, INSERM, CNRS, Paris, France.,Institut de la Vision, Paris, France
| | - Cheryl Mae Craft
- Mary D. Allen Laboratory for Vision Research, Keck School of Medicine of the University of Southern California, Los Angeles, United States.,University of Southern California Eye Institute, Keck School of Medicine of the University of Southern California, Los Angeles, United States.,Department of Ophthalmology and Cell, Keck School of Medicine of the University of Southern California, Los Angeles, United States.,Department of Neurobiology, Keck School of Medicine of the University of Southern California, Los Angeles, United States
| | - José-Alain Sahel
- Sorbonne Universités, UPMC University Paris 06, INSERM, CNRS, Paris, France.,Institut de la Vision, Paris, France.,Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, INSERM-DHOS CIC 503, Paris, France
| | - Ramin Tadayoni
- Sorbonne Universités, UPMC University Paris 06, INSERM, CNRS, Paris, France.,Institut de la Vision, Paris, France.,Department of Ophthalmology, Hôpital Lariboisièr, Paris, France
| | - Michel Paques
- Sorbonne Universités, UPMC University Paris 06, INSERM, CNRS, Paris, France.,Institut de la Vision, Paris, France.,Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, INSERM-DHOS CIC 503, Paris, France
| | - Xavier Guillonneau
- Sorbonne Universités, UPMC University Paris 06, INSERM, CNRS, Paris, France.,Institut de la Vision, Paris, France
| | - Florian Sennlaub
- Sorbonne Universités, UPMC University Paris 06, INSERM, CNRS, Paris, France.,Institut de la Vision, Paris, France
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108
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Friend or Foe? Resident Microglia vs Bone Marrow-Derived Microglia and Their Roles in the Retinal Degeneration. Mol Neurobiol 2016; 54:4094-4112. [PMID: 27318678 DOI: 10.1007/s12035-016-9960-9] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Accepted: 06/06/2016] [Indexed: 01/10/2023]
Abstract
Microglia are immune cells in the central nervous system (CNS) that originate from the yolk sac in an embryo. The renewal of the microglia pool in the adult eye consists of two components. In addition to the self-proliferation of resident cells, microglia in the CNS also derive from the bone marrow (BM). BM-derived cells pass through the blood-brain barrier (BBB) or blood-retina barrier (BRB) and differentiate into microglia under specific conditions which involves a complex mechanism. Recent studies have widely investigated the role of resident microglia and BM-derived microglia in the retinal degenerative disease. Both two cell types play dual roles and share many similar functions. However, resident microglia tend to polarize to the M1 phenotype which is pro-inflammatory and neurotoxic, whereas BM-derived microglia mainly polarize to the neuroprotective M2 phenotype in retinal degeneration. The molecular mechanism that underlines the invasion of peripheral cells has led to extensive discussions. In addition to the BBB and BRB disruption, many signaling pathways are involved in this process. Based on these studies, we discuss the roles of these two types of microglia in retinal degeneration disease and the potential clinical application of BM-derived microglia, which may benefit future therapies.
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109
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Zabel MK, Zhao L, Zhang Y, Gonzalez SR, Ma W, Wang X, Fariss RN, Wong WT. Microglial phagocytosis and activation underlying photoreceptor degeneration is regulated by CX3CL1-CX3CR1 signaling in a mouse model of retinitis pigmentosa. Glia 2016; 64:1479-91. [PMID: 27314452 PMCID: PMC4958518 DOI: 10.1002/glia.23016] [Citation(s) in RCA: 130] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2016] [Accepted: 05/20/2016] [Indexed: 12/20/2022]
Abstract
Retinitis pigmentosa (RP), a disease characterized by the progressive degeneration of mutation‐bearing photoreceptors, is a significant cause of incurable blindness in the young worldwide. Recent studies have found that activated retinal microglia contribute to photoreceptor demise via phagocytosis and proinflammatory factor production, however mechanisms regulating these contributions are not well‐defined. In this study, we investigate the role of CX3CR1, a microglia‐specific receptor, in regulating microglia‐mediated degeneration using the well‐established rd10 mouse model of RP. We found that in CX3CR1‐deficient (CX3CR1GFP/GFP) rd10 mice microglial infiltration into the photoreceptor layer was significantly augmented and associated with accelerated photoreceptor apoptosis and atrophy compared with CX3CR1‐sufficient (CX3CR1GFP/+) rd10 littermates. CX3CR1‐deficient microglia demonstrated increased phagocytosis as evidenced by (1) having increased numbers of phagosomes in vivo, (2) an increased rate of phagocytosis of fluorescent beads and photoreceptor cellular debris in vitro, and (3) increased photoreceptor phagocytosis dynamics on live cell imaging in retinal explants, indicating that CX3CR1 signaling in microglia regulates the phagocytic clearance of at‐risk photoreceptors. We also found that CX3CR1 deficiency in retinal microglia was associated with increased expression of inflammatory cytokines and microglial activation markers. Significantly, increasing CX3CL1‐CX3CR1 signaling in the rd10 retina via exogenous intravitreal delivery of recombinant CX3CL1 was effective in (1) decreasing microglial infiltration, phagocytosis and activation, and (2) improving structural and functional features of photoreceptor degeneration. These results indicate that CX3CL1‐CX3CR1 signaling is a molecular mechanism capable of modulating microglial‐mediated degeneration and represents a potential molecular target in therapeutic approaches to RP. GLIA 2016;64:1479–1491
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Affiliation(s)
- Matthew K Zabel
- Unit on Neuron-Glia Interactions in Retinal Disease, National Eye Institute, National Institutes of Health, Bethesda, Maryland
| | - Lian Zhao
- Unit on Neuron-Glia Interactions in Retinal Disease, National Eye Institute, National Institutes of Health, Bethesda, Maryland
| | - Yikui Zhang
- Unit on Neuron-Glia Interactions in Retinal Disease, National Eye Institute, National Institutes of Health, Bethesda, Maryland
| | - Shaimar R Gonzalez
- Unit on Neuron-Glia Interactions in Retinal Disease, National Eye Institute, National Institutes of Health, Bethesda, Maryland
| | - Wenxin Ma
- Unit on Neuron-Glia Interactions in Retinal Disease, National Eye Institute, National Institutes of Health, Bethesda, Maryland
| | - Xu Wang
- Unit on Neuron-Glia Interactions in Retinal Disease, National Eye Institute, National Institutes of Health, Bethesda, Maryland
| | - Robert N Fariss
- Biological Imaging Core, National Eye Institute, National Institutes of Health, Bethesda, Maryland
| | - Wai T Wong
- Unit on Neuron-Glia Interactions in Retinal Disease, National Eye Institute, National Institutes of Health, Bethesda, Maryland
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110
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TLR2/4 deficiency prevents oxygen-induced vascular degeneration and promotes revascularization by downregulating IL-17 in the retina. Sci Rep 2016; 6:27739. [PMID: 27297042 PMCID: PMC4906284 DOI: 10.1038/srep27739] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Accepted: 05/23/2016] [Indexed: 12/25/2022] Open
Abstract
Vascular degeneration is a critical pathological process in many human degenerative diseases, which need efficient ways to revascularization. However, little is known about cellular and molecular mechanisms that are used during vascular degeneration and revascularization. Here, we show that Toll-like receptor 2 and 4 (TLR2/4) double deficiency suppressed hyperoxia induced retinal vessel regression in an oxygen-induced retinopathy (OIR) model. Notably, the TLR2/4−/− mice experienced more revascularization after reduced vessel regression compared with wild-type mice, accompanied with less activation of glial cells. Mechanistically, TLR2/4 activation can tip the balance between Th17 cells and regulatory T cells towards Th17 cells, a critical source of the IL-17A. Less migration and infiltration of IL-17A-expressing proinflammatory cells but elevated regulatory T cells were observed in OIR-retinae from TLR2/4−/− mice. Coincidentally, TLR2/4 deficiency suppressed IL-17A production and increased expressions of anti-inflammatory genes. Furthermore, IL-17A promoted activation of glial cells. IL-17A blockade using a neutralizing antibody alleviated retinal cell apoptosis and glial activation in C57/B6-OIR mice, demonstrating the important role of IL-17A pathway in glial function during revascularization. Thus TLR2/4-mediated IL-17A inflammatory signaling is involved in vessel degeneration and revascularization, indicating that modulation of the TLR2/4-IL-17A pathway may be a novel therapeutic strategy for degenerative diseases.
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111
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Zhao L, Zabel MK, Wang X, Ma W, Shah P, Fariss RN, Qian H, Parkhurst CN, Gan WB, Wong WT. Microglial phagocytosis of living photoreceptors contributes to inherited retinal degeneration. EMBO Mol Med 2016; 7:1179-97. [PMID: 26139610 PMCID: PMC4568951 DOI: 10.15252/emmm.201505298] [Citation(s) in RCA: 298] [Impact Index Per Article: 37.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Retinitis pigmentosa, caused predominantly by mutations in photoreceptor genes, currently lacks comprehensive treatment. We discover that retinal microglia contribute non-cell autonomously to rod photoreceptor degeneration by primary phagocytosis of living rods. Using rd10 mice, we found that the initiation of rod degeneration is accompanied by early infiltration of microglia, upregulation of phagocytic molecules in microglia, and presentation of “eat-me” signals on mutated rods. On live-cell imaging, infiltrating microglia interact dynamically with photoreceptors via motile processes and engage in rapid phagocytic engulfment of non-apoptotic rods. Microglial contribution to rod demise is evidenced by morphological and functional amelioration of photoreceptor degeneration following genetic ablation of retinal microglia. Molecular inhibition of microglial phagocytosis using the vitronectin receptor antagonist cRGD also improved morphological and functional parameters of degeneration. Our findings highlight primary microglial phagocytosis as a contributing mechanism underlying cell death in retinitis pigmentosa and implicate microglia as a potential cellular target for therapy.
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Affiliation(s)
- Lian Zhao
- Unit on Neuron-Glia Interactions in Retinal Disease, National Eye institute National Institutes of Health, Bethesda, MD, USA
| | - Matthew K Zabel
- Unit on Neuron-Glia Interactions in Retinal Disease, National Eye institute National Institutes of Health, Bethesda, MD, USA
| | - Xu Wang
- Unit on Neuron-Glia Interactions in Retinal Disease, National Eye institute National Institutes of Health, Bethesda, MD, USA
| | - Wenxin Ma
- Unit on Neuron-Glia Interactions in Retinal Disease, National Eye institute National Institutes of Health, Bethesda, MD, USA
| | - Parth Shah
- Unit on Neuron-Glia Interactions in Retinal Disease, National Eye institute National Institutes of Health, Bethesda, MD, USA
| | - Robert N Fariss
- Biological Imaging Core, National Eye institute National Institutes of Health, Bethesda, MD, USA
| | - Haohua Qian
- Visual Function Core, National Eye institute National Institutes of Health, Bethesda, MD, USA
| | - Christopher N Parkhurst
- Department of Neuroscience and Physiology, Skirball Institute New York University School of Medicine, New York, NY, USA
| | - Wen-Biao Gan
- Department of Neuroscience and Physiology, Skirball Institute New York University School of Medicine, New York, NY, USA
| | - Wai T Wong
- Unit on Neuron-Glia Interactions in Retinal Disease, National Eye institute National Institutes of Health, Bethesda, MD, USA
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112
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Bian M, Du X, Cui J, Wang P, Wang W, Zhu W, Zhang T, Chen Y. Celastrol protects mouse retinas from bright light-induced degeneration through inhibition of oxidative stress and inflammation. J Neuroinflammation 2016; 13:50. [PMID: 26920853 PMCID: PMC4769581 DOI: 10.1186/s12974-016-0516-8] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Accepted: 02/21/2016] [Indexed: 11/29/2022] Open
Abstract
Background Photoreceptor death leads to vision impairment in several retinal degenerative disorders. Therapies protecting photoreceptor from degeneration remain to be developed. Anti-inflammation, anti-oxidative stress, and neuroprotective effects of celastrol have been demonstrated in a variety of disease models. The current study aimed to investigate the photoreceptor protective effect of celastrol. Methods Bright light-induced retinal degeneration in BALB/c mice was used, and morphological, functional, and molecular changes of retina were evaluated in the absence and presence of celastrol treatment. Results Significant morphological and functional protection was observed as a result of celastrol treatment in bright light-exposed BALB/c mice. Celastrol treatment resulted in suppression of cell death in photoreceptor cells, alleviation of oxidative stress in the retinal pigment epithelium and photoreceptors, downregulation of retinal expression of proinflammatory genes, and suppression of microglia activation and gliosis in the retina. Additionally, leukostasis was found to be induced in the retinal vasculature in light-exposed BALB/c mice, which was significantly attenuated by celastrol treatment. In vitro, celastrol attenuated all-trans-retinal-induced oxidative stress in cultured APRE19 cells. Moreover, celastrol treatment significantly suppressed lipopolysaccharides-stimulated expression of proinflammatory genes in both APRE19 and RAW264.7 cells. Conclusions The results demonstrated for the first time that celastrol prevents against light-induced retinal degeneration through inhibition of retinal oxidative stress and inflammation. Electronic supplementary material The online version of this article (doi:10.1186/s12974-016-0516-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Minjuan Bian
- Clinical Research Institute of Integrative Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, 200437, China.,Yueyang Hospital, Shanghai University of Traditional Chinese Medicine, 110 Ganhe Rd, Shanghai, 200437, China
| | - Xiaoye Du
- Clinical Research Institute of Integrative Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, 200437, China.,Yueyang Hospital, Shanghai University of Traditional Chinese Medicine, 110 Ganhe Rd, Shanghai, 200437, China
| | - Jingang Cui
- Clinical Research Institute of Integrative Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, 200437, China.,Yueyang Hospital, Shanghai University of Traditional Chinese Medicine, 110 Ganhe Rd, Shanghai, 200437, China
| | - Peiwei Wang
- Clinical Research Institute of Integrative Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, 200437, China.,Yueyang Hospital, Shanghai University of Traditional Chinese Medicine, 110 Ganhe Rd, Shanghai, 200437, China
| | - Wenjian Wang
- Clinical Research Institute of Integrative Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, 200437, China.,Yueyang Hospital, Shanghai University of Traditional Chinese Medicine, 110 Ganhe Rd, Shanghai, 200437, China
| | - Weiliang Zhu
- Shanghai Institute of Materia Medica, Shanghai, 201203, China
| | - Teng Zhang
- Clinical Research Institute of Integrative Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, 200437, China. .,Yueyang Hospital, Shanghai University of Traditional Chinese Medicine, 110 Ganhe Rd, Shanghai, 200437, China.
| | - Yu Chen
- Clinical Research Institute of Integrative Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, 200437, China. .,Yueyang Hospital, Shanghai University of Traditional Chinese Medicine, 110 Ganhe Rd, Shanghai, 200437, China.
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113
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Fate mapping reveals that microglia and recruited monocyte-derived macrophages are definitively distinguishable by phenotype in the retina. Sci Rep 2016; 6:20636. [PMID: 26856416 PMCID: PMC4746646 DOI: 10.1038/srep20636] [Citation(s) in RCA: 139] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Accepted: 01/06/2016] [Indexed: 12/14/2022] Open
Abstract
The recent paradigm shift that microglia are yolk sac-derived, not hematopoietic-derived, is reshaping our knowledge about the isolated role of microglia in CNS diseases, including degenerative conditions of the retina. However, unraveling microglial-specific functions has been hindered by phenotypic overlap of microglia with monocyte-derived macrophages. The latter are differentiated from recruited monocytes in neuroinflammation, including retina. Here we demonstrate the use of fate mapping wherein microglia and monocyte-derived cells are endogenously labeled with different fluorescent reporters. Combining this method with 12-color flow cytometry, we show that these two populations are definitively distinguishable by phenotype in retina. We prove that retinal microglia have a unique CD45(lo) CD11c(lo) F4/80(lo) I-A/I-E(-) signature, conserved in the steady state and during retinal injury. The latter was observed in the widely used light-induced retinal degeneration model and corroborated in other models, including whole-body irradiation/bone-marrow transplantation. The literature contains conflicting observations about whether microglia, including in the retina, increase expression of these markers in neuroinflammation. We show that monocyte-derived macrophages have elevated expression of these surface markers, not microglia. Our resolution of such phenotypic differences may serve as a robust way to help characterize isolated roles of these cells in retinal neuroinflammation and possibly elsewhere in CNS.
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114
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APOE Isoforms Control Pathogenic Subretinal Inflammation in Age-Related Macular Degeneration. J Neurosci 2016; 35:13568-76. [PMID: 26446211 DOI: 10.1523/jneurosci.2468-15.2015] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
UNLABELLED Contrary to Alzheimer's disease (AD), the APOE2 allele increases and the APOE4 allele reduces the risk to develop age-related macular degeneration (AMD) compared with the most common APOE3 allele. The underlying mechanism for this association with AMD and the reason for the puzzling difference with AD are unknown. We previously demonstrated that pathogenic subretinal mononuclear phagocytes (MPs) accumulate in Cx3cr1-deficient mice due to the overexpression of APOE, interleukin-6, and CC chemokine ligand 2 (CCL2). We here show using targeted replacement mice expressing the human APOE isoforms (TRE2, TRE3, and TRE4) that MPs of TRE2 mice express increased levels of APOE, interleukin-6, and CCL2 and develop subretinal MP accumulation, photoreceptor degeneration, and exaggerated choroidal neovascularization similar to AMD. Pharmacological inhibition of the cytokine induction inhibited the pathogenic subretinal inflammation. In the context of APOE-dependent subretinal inflammation in Cx3cr1(GFP/GFP) mice, the APOE4 allele led to diminished APOE and CCL2 levels and protected Cx3cr1(GFP/GFP) mice against harmful subretinal MP accumulation observed in Cx3cr1(GFP/GFP)TRE3 mice. Our study shows that pathogenic subretinal inflammation is APOE isoform-dependent and provides the rationale for the previously unexplained implication of the APOE2 isoform as a risk factor and the APOE4 isoform as a protective factor in AMD pathogenesis. SIGNIFICANCE STATEMENT The understanding of how genetic predisposing factors, which play a major role in age-related macular degeneration (AMD), participate in its pathogenesis is an important clue to decipher the pathomechanism and develop efficient therapies. In this study, we used transgenic, targeted replacement mice that carry the three human APOE isoform-defining sequences at the mouse APOE chromosomal location and express the human APOE isoforms. Our study is the first to show how APOE2 provokes and APOE4 inhibits the cardinal AMD features, inflammation, degeneration, and exaggerated neovascularization. Our findings reflect the clinical association of the genetic predisposition that was recently confirmed in a major pooled analysis. They emphasize the role of APOE in inflammation and inflammation in AMD.
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115
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Montserrat-de la Paz S, Naranjo MC, Bermudez B, Lopez S, Moreda W, Abia R, Muriana FJG. Postprandial dietary fatty acids exert divergent inflammatory responses in retinal-pigmented epithelium cells. Food Funct 2016; 7:1345-53. [DOI: 10.1039/c6fo00136j] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Postprandial triglyceride-rich lipoproteins (TRLs) lead to a complex series of events that are potentially oxidative and inflammatory.
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Affiliation(s)
| | - M. Carmen Naranjo
- Laboratory of Cellular and Molecular Nutrition
- Instituto de la Grasa
- CSIC
- 41013 Seville
- Spain
| | - Beatriz Bermudez
- Department of Pharmacology
- School of Pharmacy
- University of Seville
- 41012 Seville
- Spain
| | - Sergio Lopez
- Laboratory of Cellular and Molecular Nutrition
- Instituto de la Grasa
- CSIC
- 41013 Seville
- Spain
| | - Wenceslao Moreda
- Laboratory of Olive Oil Quality
- Purity and Technology
- Instituto de la Grasa
- CSIC
- 41013 Seville
| | - Rocio Abia
- Laboratory of Cellular and Molecular Nutrition
- Instituto de la Grasa
- CSIC
- 41013 Seville
- Spain
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116
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Taguchi M, Shinozaki Y, Kashiwagi K, Shigetomi E, Robaye B, Koizumi S. Müller cell-mediated neurite outgrowth of the retinal ganglion cells via P2Y 6 receptor signals. J Neurochem 2015; 136:741-751. [PMID: 26560804 DOI: 10.1111/jnc.13427] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Revised: 10/22/2015] [Accepted: 10/30/2015] [Indexed: 12/27/2022]
Abstract
Müller cells, the primary macroglia of the retina, support various functions of retinal ganglion cells (RGCs). Here, we demonstrate a nucleotide-mediated communication between these two types of cells, by which Müller cells control neurite outgrowth of RGCs by activation of P2 receptors such as P2Y6 . Cultured mouse RGCs had significantly enhanced neurite outgrowth when cultured with either cultured mouse Müller cells or conditioned medium derived from Müller cells, and this was completely inhibited by the nucleotide-degrading enzyme, apyrase. This increase in outgrowth was mimicked by exogenously applied nucleotides such as ATP, uridine triphosphate, and uridine diphosphate. Pharmacological and genetic analysis revealed that P2Y6 receptor in RGCs was responsible for the increased neurite outgrowth. P2Y6 receptor was expressed in the ganglion cell layer of the retina and in RGC primary cultures. High performance liquid chromatography has revealed that Müller cells constitutively release uridine triphosphate, which is immediately metabolized into uridine diphosphate, an endogenous agonist for P2Y6 receptor. In the in vitro ocular hypertension model (i.e., glaucoma model), neurite outgrowth in RGCs was significantly reduced, which was associated with a decrease in P2Y6 receptors. Taken together, Müller cells control neurite outgrowth of RGCs by activating P2 receptors such as P2Y6 receptor, and the receptor expression level might be down-regulated in glaucoma. Müller cells support various functions of retina including those of retinal ganglion cells (RGCs). Here, we report an importance of nucleotide-mediated communication between these two types of cells. Müller cells were found to release uridine diphosphate (UTD), uridine triphosphate (UTP), and activate P2Y6 receptors in RGCs, which was essential for neurite outgrowth of RGCs. In addition, P2Y6 receptors in RGCs were reduced in a glaucoma model in vitro, suggesting an involvement of their dysfunction in the pathogenesis of glaucoma.
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Affiliation(s)
- Masanori Taguchi
- Department of Neuropharmacology, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Chuo, Yamanashi, Japan
| | - Youichi Shinozaki
- Department of Neuropharmacology, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Chuo, Yamanashi, Japan
| | - Kenji Kashiwagi
- Department of Ophthalmology, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Chuo, Yamanashi, Japan
| | - Eiji Shigetomi
- Department of Neuropharmacology, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Chuo, Yamanashi, Japan
| | - Bernard Robaye
- Institute of Interdisciplinary Research, Institute of Biology and Molecular Medicine, Université Libre de Bruxelles, Gosselies, Belgium
| | - Schuichi Koizumi
- Department of Neuropharmacology, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Chuo, Yamanashi, Japan
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117
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Perusek L, Sahu B, Parmar T, Maeno H, Arai E, Le YZ, Subauste CS, Chen Y, Palczewski K, Maeda A. Di-retinoid-pyridinium-ethanolamine (A2E) Accumulation and the Maintenance of the Visual Cycle Are Independent of Atg7-mediated Autophagy in the Retinal Pigmented Epithelium. J Biol Chem 2015; 290:29035-44. [PMID: 26468292 PMCID: PMC4661415 DOI: 10.1074/jbc.m115.682310] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Revised: 10/03/2015] [Indexed: 01/10/2023] Open
Abstract
Autophagy is an evolutionarily conserved catabolic mechanism that relieves cellular stress by removing/recycling damaged organelles and debris through the action of lysosomes. Compromised autophagy has been implicated in many neurodegenerative diseases, including retinal degeneration. Here we examined retinal phenotypes resulting from RPE-specific deletion of the autophagy regulatory gene Atg7 by generating Atg7(flox/flox);VMD2-rtTA-cre+ mice to determine whether autophagy is essential for RPE functions including retinoid recycling. Atg7-deficient RPE displayed abnormal morphology with increased RPE thickness, cellular debris and vacuole formation indicating that autophagy is important in maintaining RPE homeostasis. In contrast, 11-cis-retinal content, ERGs and retinal histology were normal in mice with Atg7-deficient RPE in both fasted and fed states. Because A2E accumulation in the RPE is associated with pathogenesis of both Stargardt disease and age-related macular degeneration (AMD) in humans, deletion of Abca4 was introduced into Atg7(flox/flox);VMD2-rtTA-cre+ mice to investigate the role of autophagy during A2E accumulation. Comparable A2E concentrations were detected in the eyes of 6-month-old mice with and without Atg7 from both Abca4(-/-) and Abca4(+/+) backgrounds. To identify other autophagy-related molecules involved in A2E accumulation, we performed gene expression array analysis on A2E-treated human RPE cells and found up-regulation of four autophagy related genes; DRAM1, NPC1, CASP3, and EIF2AK3/PERK. These observations indicate that Atg7-mediated autophagy is dispensable for retinoid recycling and A2E deposition; however, autophagy plays a role in coping with stress caused by A2E accumulation.
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Affiliation(s)
| | | | - Tanu Parmar
- From the Departments of Ophthalmology and Visual Sciences
| | - Hiroshi Maeno
- From the Departments of Ophthalmology and Visual Sciences
| | - Eisuke Arai
- From the Departments of Ophthalmology and Visual Sciences
| | - Yun-Zheng Le
- Departments of Medicine Endocrinology, Cell Biology, and Ophthalmology and Harold Hamm Diabetes Center, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104
| | - Carlos S Subauste
- Medicine, Case Western Reserve University, Cleveland, Ohio 44106 and
| | - Yu Chen
- Pharmacology and Cleveland Center for Membrane and Structural Biology, and
| | | | - Akiko Maeda
- From the Departments of Ophthalmology and Visual Sciences, Pharmacology and Cleveland Center for Membrane and Structural Biology, and
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118
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Hampton BM, Schwartz SG, Brantley MA, Flynn HW. Update on genetics and diabetic retinopathy. Clin Ophthalmol 2015; 9:2175-93. [PMID: 26648684 PMCID: PMC4664538 DOI: 10.2147/opth.s94508] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Clinical risk factors for diabetic retinopathy (DR), such as duration of disease and degree of glucose control, do not adequately predict disease progression in individual patients, suggesting the presence of a genetic component. Multiple smaller studies have investigated genotype–phenotype correlations in genes encoding vascular endothelial growth factor, aldose reductase, the receptor for advanced glycation end products, and many others. In general, reported results have been conflicting, due to factors including small sample sizes, variations in study design, differences in clinical end points, and underlying genetic differences between study groups. At this time, there is no confirmed association with any risk allele reported. As we continue to collect data from additional studies, the role of genetics in DR may become more apparent.
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Affiliation(s)
- Blake M Hampton
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Stephen G Schwartz
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Milam A Brantley
- Department of Ophthalmology, Vanderbilt Eye Institute, Nashville, TN, USA
| | - Harry W Flynn
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
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119
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Kohno H, Koso H, Okano K, Sundermeier TR, Saito S, Watanabe S, Tsuneoka H, Sakai T. Expression pattern of Ccr2 and Cx3cr1 in inherited retinal degeneration. J Neuroinflammation 2015; 12:188. [PMID: 26458944 PMCID: PMC4603985 DOI: 10.1186/s12974-015-0408-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Accepted: 10/02/2015] [Indexed: 12/27/2022] Open
Abstract
Background Though accumulating evidence suggests that microglia, resident macrophages in the retina, and bone marrow-derived macrophages can cause retinal inflammation which accelerates photoreceptor cell death, the details of how these cells are activated during retinal degeneration (RD) remain uncertain. Therefore, it is important to clarify which cells play a dominant role in fueling retinal inflammation. However, distinguishing between microglia and macrophages is difficult using conventional techniques such as cell markers (e.g., Iba-1). Recently, two mouse models for visualizing chemokine receptors were established, Cx3cr1GFP/GFP and Ccr2RFP/RFP mice. As Cx3cr1 is expressed in microglia and Ccr2 is reportedly expressed in activated macrophages, these mice have the potential to distinguish microglia and macrophages, yielding novel information about the activation of these inflammatory cells and their individual roles in retinal inflammation. Methods In this study, c-mer proto-oncogene tyrosine kinase (Mertk)−/− mice, which show photoreceptor cell death due to defective retinal pigment epithelium phagocytosis, were employed as an animal model of RD. Mertk−/−Cx3cr1GFP/+Ccr2RFP/+ mice were established by breeding Mertk−/−, Cx3cr1GFP/GFP, and Ccr2RFP/RFP mice. The retinal morphology and pattern of inflammatory cell activation and invasion of Mertk−/−Cx3cr1GFP/+Ccr2RFP/+ mice were evaluated using retina and retinal pigment epithelium (RPE) flat mounts, retinal sections, and flow cytometry. Results Four-week-old Mertk−/−Cx3cr1GFP/+Ccr2RFP/+ mice showed Cx3cr1-GFP-positive microglia in the inner retina. Cx3cr1-GFP and Ccr2-RFP dual positive activated microglia were observed in the outer retina and subretinal space of 6- and 8-week-old animals. Ccr2-RFP single positive bone marrow-derived macrophages were observed to migrate into the retina of Mertk−/−Cx3cr1GFP/+Ccr2RFP/+ mice. These invading cells were still observed in the subretinal space in 18-week-old animals. Conclusions Cx3cr1-GFP-positive microglia and Ccr2-RFP-positive macrophages were distinguishable in the retinas of Mertk−/−Cx3cr1GFP/+Ccr2RFP/+ mice. In addition, Ccr2 expression in Cx3cr1 positive microglia is a feature of microglial activation in RD. Mertk−/−Cx3cr1GFP/+Ccr2RFP/+ mice enabled observation of microglial activation over time during RD and may be useful for developing inflammation-targeted treatment strategies for RD in the future.
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Affiliation(s)
- Hideo Kohno
- Department of Ophthalmology, The Jikei University School of Medicine, 105-8461, Tokyo, Japan. .,Tokyu Hospital, 145-0062, Tokyo, Japan.
| | - Hideto Koso
- Division of Molecular and Developmental Biology, The Institute of Medical Science, The University of Tokyo, 108-8639, Tokyo, Japan
| | - Kiichiro Okano
- Department of Ophthalmology, The Jikei University School of Medicine, 105-8461, Tokyo, Japan
| | - Thomas R Sundermeier
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Saburo Saito
- Department of Molecular Immunology, The Jikei University School of Medicine, 105-8461, Tokyo, Japan
| | - Sumiko Watanabe
- Division of Molecular and Developmental Biology, The Institute of Medical Science, The University of Tokyo, 108-8639, Tokyo, Japan
| | - Hiroshi Tsuneoka
- Department of Ophthalmology, The Jikei University School of Medicine, 105-8461, Tokyo, Japan
| | - Tsutomu Sakai
- Department of Ophthalmology, The Jikei University School of Medicine, 105-8461, Tokyo, Japan.
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120
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Ildefonso CJ, Jaime H, Rahman MM, Li Q, Boye SE, Hauswirth WW, Lucas AR, McFadden G, Lewin AS. Gene delivery of a viral anti-inflammatory protein to combat ocular inflammation. Hum Gene Ther 2015; 26:59-68. [PMID: 25420215 DOI: 10.1089/hum.2014.089] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Inflammation of the retina is a contributing factor in ocular diseases such as uveitis, diabetic retinopathy, and age-related macular degeneration (AMD). The M013 immunomodulatory protein from myxoma virus has been shown to interfere with the proinflammatory signaling pathways involving both the NLRP3 inflammasome and NF-κB. We have developed and characterized an adeno-associated viral (AAV) vector that delivers a secretable and cell-penetrating form of the M013 protein (TatM013). The expressed TatM013 protein was secreted and blocked the endotoxin-induced secretion of interleukin (IL)-1β in monocyte-derived cells and the reactive aldehyde-induced secretion of IL-1β in retinal pigment epithelium cells. The local anti-inflammatory effects of AAV-delivered TatM013 were evaluated in an endotoxin-induced uveitis (EIU) mouse model after intravitreal injection of mice with an AAV2-based vector carrying either TatM013 fused to a secreted green fluorescent protein (GFP) tag (sGFP-TatM013) or GFP. Expression of the sGFP-TatM013 transgene was demonstrated by fluorescence funduscopy in living mice. In EIU, the number of infiltrating cells and the concentration of IL-1β in the vitreous body were significantly lower in the eyes injected with AAV-sGFP-TatM013 compared with the eyes injected with control AAV-GFP. These results suggest that a virus-derived inhibitor of the innate immune response, when delivered via AAV, could be a generalized therapy for various inflammatory diseases of the eye.
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Affiliation(s)
- Cristhian J Ildefonso
- 1 Department of Molecular Genetics and Microbiology, University of Florida College of Medicine , Gainesville, FL 32610
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Schur RM, Sheng L, Sahu B, Yu G, Gao S, Yu X, Maeda A, Palczewski K, Lu ZR. Manganese-Enhanced MRI for Preclinical Evaluation of Retinal Degeneration Treatments. Invest Ophthalmol Vis Sci 2015. [PMID: 26225634 DOI: 10.1167/iovs.15-16522] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
PURPOSE Apply manganese-enhanced magnetic resonance imaging (MEMRI) to assess ion channel activity and structure of retinas from mice subject to light-induced retinal degeneration treated with prophylactic agents. METHODS Abca4(-/-)Rdh8(-/-) double knockout mice with and without prophylactic retinylamine (Ret-NH2) treatment were illuminated with strong light. Manganese-enhanced MRI was used to image the retina 2 hours after intravitreous injection of MnCl2 into one eye. Contrast-enhanced MRIs of the retina and vitreous humor in each experimental group were assessed and correlated with the treatment. Findings were compared with standard structural and functional assessments of the retina by optical coherence tomography (OCT), histology, and electroretinography (ERG). RESULTS Manganese-enhanced MRI contrast in the retina was high in nonilluminated and illuminated Ret-NH2-treated mice, whereas no enhancement was evident in the retina of the light-illuminated mice without Ret-NH2 treatment (P < 0.0005). A relatively high signal enhancement was also observed in the vitreous humor of mice treated with Ret-NH2. Strong MEMRI signal enhancement in the retinas of mice treated with retinylamine was correlated with their structural integrity and function evidenced by OCT, histology, and a strong ERG light response. CONCLUSIONS Manganese-enhanced MRI has the potential to assess the response of the retina to prophylactic treatment based on the measurement of ion channel activity. This approach could be used as a complementary tool in preclinical development of new prophylactic therapies for retinopathies.
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Affiliation(s)
- Rebecca M Schur
- Department of Biomedical Engineering School of Engineering, Case Western Reserve University, Cleveland, Ohio, United States
| | - Li Sheng
- Department of Biomedical Engineering School of Engineering, Case Western Reserve University, Cleveland, Ohio, United States
| | - Bhubanananda Sahu
- Department of Ophthalmology and Visual Sciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio, United States
| | - Guanping Yu
- Department of Biomedical Engineering School of Engineering, Case Western Reserve University, Cleveland, Ohio, United States
| | - Songqi Gao
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, United States
| | - Xin Yu
- Department of Biomedical Engineering School of Engineering, Case Western Reserve University, Cleveland, Ohio, United States
| | - Akiko Maeda
- Department of Ophthalmology and Visual Sciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio, United States 3Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, United States
| | - Krzysztof Palczewski
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, United States
| | - Zheng-Rong Lu
- Department of Biomedical Engineering School of Engineering, Case Western Reserve University, Cleveland, Ohio, United States
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Housset M, Sennlaub F. Thrombospondin-1 and Pathogenesis of Age-Related Macular Degeneration. J Ocul Pharmacol Ther 2015; 31:406-12. [DOI: 10.1089/jop.2015.0023] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Affiliation(s)
- Michael Housset
- Sorbonne Universités, UPMC Univ Paris 06, UMR_S 968, Institut de la Vision, Paris, France
- CNRS, UMR_7210, Paris, France
- INSERM, U968, Paris, France
| | - Florian Sennlaub
- Sorbonne Universités, UPMC Univ Paris 06, UMR_S 968, Institut de la Vision, Paris, France
- CNRS, UMR_7210, Paris, France
- INSERM, U968, Paris, France
- Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, DHU ViewMaintain, INSERM-DHOS CIC 1423, Paris, France
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Levy O, Calippe B, Lavalette S, Hu SJ, Raoul W, Dominguez E, Housset M, Paques M, Sahel JA, Bemelmans AP, Combadiere C, Guillonneau X, Sennlaub F. Apolipoprotein E promotes subretinal mononuclear phagocyte survival and chronic inflammation in age-related macular degeneration. EMBO Mol Med 2015; 7:211-26. [PMID: 25604058 PMCID: PMC4328649 DOI: 10.15252/emmm.201404524] [Citation(s) in RCA: 93] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Physiologically, the retinal pigment epithelium (RPE) expresses immunosuppressive signals such as FAS ligand (FASL), which prevents the accumulation of leukocytes in the subretinal space. Age-related macular degeneration (AMD) is associated with a breakdown of the subretinal immunosuppressive environment and chronic accumulation of mononuclear phagocytes (MPs). We show that subretinal MPs in AMD patients accumulate on the RPE and express high levels of APOE. MPs of Cx3cr1(-/-) mice that develop MP accumulation on the RPE, photoreceptor degeneration, and increased choroidal neovascularization similarly express high levels of APOE. ApoE deletion in Cx3cr1(-/-) mice prevents pathogenic age- and stress-induced subretinal MP accumulation. We demonstrate that increased APOE levels induce IL-6 in MPs via the activation of the TLR2-CD14-dependent innate immunity receptor cluster. IL-6 in turn represses RPE FasL expression and prolongs subretinal MP survival. This mechanism may account, in part, for the MP accumulation observed in Cx3cr1(-/-) mice. Our results underline the inflammatory role of APOE in sterile inflammation in the immunosuppressive subretinal space. They provide rationale for the implication of IL-6 in AMD and open avenues toward therapies inhibiting pathogenic chronic inflammation in late AMD.
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Affiliation(s)
- Olivier Levy
- INSERM, Paris, France UPMC Univ Paris 06 UMR_S 968 Institut de la Vision, Paris, France Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts INSERM-DHOS CIC 503, Paris, France
| | - Bertrand Calippe
- INSERM, Paris, France UPMC Univ Paris 06 UMR_S 968 Institut de la Vision, Paris, France Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts INSERM-DHOS CIC 503, Paris, France
| | - Sophie Lavalette
- INSERM, Paris, France UPMC Univ Paris 06 UMR_S 968 Institut de la Vision, Paris, France Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts INSERM-DHOS CIC 503, Paris, France
| | - Shulong J Hu
- INSERM, Paris, France UPMC Univ Paris 06 UMR_S 968 Institut de la Vision, Paris, France Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts INSERM-DHOS CIC 503, Paris, France
| | - William Raoul
- INSERM, Paris, France UPMC Univ Paris 06 UMR_S 968 Institut de la Vision, Paris, France Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts INSERM-DHOS CIC 503, Paris, France
| | - Elisa Dominguez
- INSERM, Paris, France UPMC Univ Paris 06 UMR_S 968 Institut de la Vision, Paris, France Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts INSERM-DHOS CIC 503, Paris, France
| | - Michael Housset
- INSERM, Paris, France UPMC Univ Paris 06 UMR_S 968 Institut de la Vision, Paris, France Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts INSERM-DHOS CIC 503, Paris, France
| | - Michel Paques
- INSERM, Paris, France UPMC Univ Paris 06 UMR_S 968 Institut de la Vision, Paris, France Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts INSERM-DHOS CIC 503, Paris, France
| | - José-Alain Sahel
- INSERM, Paris, France UPMC Univ Paris 06 UMR_S 968 Institut de la Vision, Paris, France Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts INSERM-DHOS CIC 503, Paris, France
| | - Alexis-Pierre Bemelmans
- INSERM, Paris, France UPMC Univ Paris 06 UMR_S 968 Institut de la Vision, Paris, France Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts INSERM-DHOS CIC 503, Paris, France CEA DSV I²BM Molecular Imaging Research Center (MIRCen), Fontenay-aux-Roses, France CNRS CEA URA 2210, Fontenay-aux-Roses, France
| | - Christophe Combadiere
- Sorbonne Universités, UPMC Univ Paris 06 CR7 Centre d'Immunologie et des Maladies Infectieuses (CIMI-Paris), Paris, France INSERM U1135 CIMI-Paris, Paris, France CNRS ERL 8255 CIMI-Paris, Paris, France
| | - Xavier Guillonneau
- INSERM, Paris, France UPMC Univ Paris 06 UMR_S 968 Institut de la Vision, Paris, France Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts INSERM-DHOS CIC 503, Paris, France
| | - Florian Sennlaub
- INSERM, Paris, France UPMC Univ Paris 06 UMR_S 968 Institut de la Vision, Paris, France Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts INSERM-DHOS CIC 503, Paris, France
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Upregulation of P2RX7 in Cx3cr1-Deficient Mononuclear Phagocytes Leads to Increased Interleukin-1β Secretion and Photoreceptor Neurodegeneration. J Neurosci 2015; 35:6987-96. [PMID: 25948251 DOI: 10.1523/jneurosci.3955-14.2015] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Photoreceptor degeneration in age-related macular degeneration (AMD) is associated with an infiltration and chronic accumulation of mononuclear phagocytes (MPs). We have previously shown that Cx3cr1-deficient mice develop age- and stress- related subretinal accumulation of MPs, which is associated with photoreceptor degeneration. Cx3cr1-deficient MPs have been shown to increase neuronal apoptosis through IL-1β in neuroinflammation of the brain. The reason for increased IL-1β secretion from Cx3cr1-deficient MPs, and whether IL-1β is responsible for increased photoreceptor apoptosis in Cx3cr1-deficient mice, has not been elucidated. Here we show that Cx3cr1-deficient MPs express increased surface P2X7 receptor (P2RX7), which stimulates IL-1β maturation and secretion. P2RX7 and IL-1β inhibition efficiently blunted Cx3cr1-MP-dependent photoreceptor apoptosis in a monocyte/retina coculture system and in light-induced subretinal inflammation of Cx3cr1-deficient mice in vivo. Our results provide an explanation for increased CX3CR1-dependent IL-1β secretion and suggest that IL-1β or P2RX7 inhibition can help inhibit the inflammation-associated photoreceptor cell loss in late AMD, including geographic atrophy, for which no efficient treatment currently exists.
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Orban T, Johnson WM, Dong Z, Maeda T, Maeda A, Sakai T, Tsuneoka H, Mieyal JJ, Palczewski K. Serum levels of lipid metabolites in age-related macular degeneration. FASEB J 2015; 29:4579-88. [PMID: 26187344 DOI: 10.1096/fj.15-275289] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Accepted: 07/06/2015] [Indexed: 01/24/2023]
Abstract
Age-related macular degeneration (AMD) is a neurodegenerative disease that causes adult-onset blindness. There are 2 forms of this progressive disease: wet and dry. Currently there is no cure for AMD, but several treatment options have started to emerge making early detection critical for therapeutic success. Analysis of the eyes of Abca4(-/-)Rdh8(-/-) mice that display light-induced retinal degeneration indicates that 11-cis-retinal and docosahexaenoic acid (DHA) levels were significantly decreased as compared with the eyes of control dark-adapted C57BL/6J mice. In addition, exposure to intense light correlated with higher levels of prostaglandin G2 in the eyes of Abca4(-/-)Rdh8(-/-) mice. Intense light exposure also lowered DHA levels in the eyes of wild-type C57BL/6J mice without discernible retinal degeneration. Analysis of human serum from patients with AMD recapitulated these dysregulated DHA levels and revealed dysregulation of arachidonic acid (AA) levels as well (∼32% increase in patients with AMD compared with average levels in healthy individuals). From these observations, we then built a statistical model that included levels of DHA and AA from human serum. This model had a 74% probability of correctly identifying patients with AMD from controls. Addition of a genetic analysis for one of the most prevalent amino acid substitutions in the age-related maculopathy susceptibility 2 gene linked to AMD, Ala(69)→Ser, did not improve the statistical model. Thus, we have characterized a reliable method with the potential to detect AMD without a genetic component, paving the way for a larger-scale clinical evaluation. Our studies on mouse models along with the analysis of human serum suggest that our small molecule-based model may serve as an effective tool to estimate the risk of developing AMD.
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Affiliation(s)
- Tivadar Orban
- *Department of Pharmacology and Department of Ophthalmology and Visual Sciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA; Polgenix, Incorporated, Cleveland, Ohio, USA; Department of Ophthalmology, Jikei University School of Medicine, Tokyo, Japan; and Louis Stokes Veterans Affairs Medical Research Center, Cleveland, Ohio, USA
| | - William M Johnson
- *Department of Pharmacology and Department of Ophthalmology and Visual Sciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA; Polgenix, Incorporated, Cleveland, Ohio, USA; Department of Ophthalmology, Jikei University School of Medicine, Tokyo, Japan; and Louis Stokes Veterans Affairs Medical Research Center, Cleveland, Ohio, USA
| | - Zhiqian Dong
- *Department of Pharmacology and Department of Ophthalmology and Visual Sciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA; Polgenix, Incorporated, Cleveland, Ohio, USA; Department of Ophthalmology, Jikei University School of Medicine, Tokyo, Japan; and Louis Stokes Veterans Affairs Medical Research Center, Cleveland, Ohio, USA
| | - Tadao Maeda
- *Department of Pharmacology and Department of Ophthalmology and Visual Sciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA; Polgenix, Incorporated, Cleveland, Ohio, USA; Department of Ophthalmology, Jikei University School of Medicine, Tokyo, Japan; and Louis Stokes Veterans Affairs Medical Research Center, Cleveland, Ohio, USA
| | - Akiko Maeda
- *Department of Pharmacology and Department of Ophthalmology and Visual Sciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA; Polgenix, Incorporated, Cleveland, Ohio, USA; Department of Ophthalmology, Jikei University School of Medicine, Tokyo, Japan; and Louis Stokes Veterans Affairs Medical Research Center, Cleveland, Ohio, USA
| | - Tsutomu Sakai
- *Department of Pharmacology and Department of Ophthalmology and Visual Sciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA; Polgenix, Incorporated, Cleveland, Ohio, USA; Department of Ophthalmology, Jikei University School of Medicine, Tokyo, Japan; and Louis Stokes Veterans Affairs Medical Research Center, Cleveland, Ohio, USA
| | - Hiroshi Tsuneoka
- *Department of Pharmacology and Department of Ophthalmology and Visual Sciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA; Polgenix, Incorporated, Cleveland, Ohio, USA; Department of Ophthalmology, Jikei University School of Medicine, Tokyo, Japan; and Louis Stokes Veterans Affairs Medical Research Center, Cleveland, Ohio, USA
| | - John J Mieyal
- *Department of Pharmacology and Department of Ophthalmology and Visual Sciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA; Polgenix, Incorporated, Cleveland, Ohio, USA; Department of Ophthalmology, Jikei University School of Medicine, Tokyo, Japan; and Louis Stokes Veterans Affairs Medical Research Center, Cleveland, Ohio, USA
| | - Krzysztof Palczewski
- *Department of Pharmacology and Department of Ophthalmology and Visual Sciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA; Polgenix, Incorporated, Cleveland, Ohio, USA; Department of Ophthalmology, Jikei University School of Medicine, Tokyo, Japan; and Louis Stokes Veterans Affairs Medical Research Center, Cleveland, Ohio, USA
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Romano GL, Platania CBM, Forte S, Salomone S, Drago F, Bucolo C. MicroRNA target prediction in glaucoma. PROGRESS IN BRAIN RESEARCH 2015; 220:217-40. [PMID: 26497793 DOI: 10.1016/bs.pbr.2015.04.013] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Glaucoma is a progressive optic neuropathy and is one of the leading causes of blindness in the industrialized countries. The aim of this study is to investigate microRNA (miRNA) regulation in glaucoma and other neurodegenerative diseases, that share similar pathways, by means of in silico approaches such as bibliographic search and access to bioinformatic resources. First of all, data mining was carried out on Human miRNA Disease Database (HMDD) and miR2Disease databases. Then, predictions of deregulated miRNAs were carried out accessing to microrna.org database. Finally, the potential combinatorial effect of miRNAs, on regulation of biochemical pathways, was studied by an enrichment analysis performed by DIANA-miRPath v.2.0. We found, from literature search, 8 deregulated miRNAs in glaucoma and 9 and 23 in age-related macular degeneration (AMD) and Alzheimer's disease (AD), respectively. One miRNA is commonly deregulated in glaucoma and AMD (miR-23a). Two miRNAs (miR-29a, miR-29b) are common to glaucoma and AD, and four miRNAs were identified to be commonly deregulated in AMD and AD (miR-9, miR-21, miR-34a, miR-146a). The match of the miRNA common to glaucoma and the other two neurodegenerative diseases (AMD and AD) did not generate any output. Enrichment of information has been reached through miRNAs prediction: 88 predicted miRNAs are common to glaucoma and AMD, 19 are common to glaucoma and AD, and 9 are common to AMD and AD. Indeed, predicted miRNAs common to the three neurodegenerative diseases are nine (miR-107, miR-137, miR-146a, miR-181c, miR-197, miR-21, miR-22, miR-590, miR-9). DIANA-miRPath predicted that those nine miRNAs might regulate pathways involved in inflammation. The findings hereby obtained provide a valuable hint to assess deregulation of specific miRNA, as potential biomarkers and therapeutic targets, in glaucoma and other neurodegenerative diseases by means of preclinical and clinical studies.
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Affiliation(s)
- Giovanni Luca Romano
- Department of Biomedical and Biotechnological Sciences, Section of Pharmacology, University of Catania, Catania, Italy
| | - Chiara Bianca Maria Platania
- Department of Biomedical and Biotechnological Sciences, Section of Pharmacology, University of Catania, Catania, Italy
| | | | - Salvatore Salomone
- Department of Biomedical and Biotechnological Sciences, Section of Pharmacology, University of Catania, Catania, Italy
| | - Filippo Drago
- Department of Biomedical and Biotechnological Sciences, Section of Pharmacology, University of Catania, Catania, Italy
| | - Claudio Bucolo
- Department of Biomedical and Biotechnological Sciences, Section of Pharmacology, University of Catania, Catania, Italy.
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Guadagni V, Novelli E, Piano I, Gargini C, Strettoi E. Pharmacological approaches to retinitis pigmentosa: A laboratory perspective. Prog Retin Eye Res 2015; 48:62-81. [PMID: 26113212 DOI: 10.1016/j.preteyeres.2015.06.005] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Revised: 06/05/2015] [Accepted: 06/11/2015] [Indexed: 01/08/2023]
Abstract
Retinal photoreceptors are highly specialized and performing neurons. Their cellular architecture is exquisitely designed to host a high concentration of molecules involved in light capture, phototransduction, electric and chemical signaling, membrane and molecular turnover, light and dark adaption, network activities etc. Such high efficiency and molecular complexity require a great metabolic demand, altogether conferring to photoreceptors particular susceptibility to external and internal insults, whose occurrence usually precipitate into degeneration of these cells and blindness. In Retinitis Pigmentosa, an impressive number of mutations in genes expressed in the retina and coding for a large varieties of proteins leads to the progressive death of photoreceptors and blindness. Recent advances in molecular tools have greatly facilitated the identification of the underlying genetics and molecular bases of RP leading to the successful implementation of gene therapy for some types of mutations, with visual restoration in human patients. Yet, genetic heterogeneity of RP makes mutation-independent approaches highly desirable, although many obstacles pave the way to general strategies for treating this complex disease, which remains orphan. The review will focus on treatments for RP based on pharmacological tools, choosing, among the many ongoing studies, approaches which rely on strong experimental evidence or rationale. For perspective treatments, new concepts are foreseen to emerge from basic studies elucidating the pathways connecting the primary mutations to photoreceptor death, possibly revealing common molecular targets for drug intervention.
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Affiliation(s)
- Viviana Guadagni
- Neuroscience Institute, Italian National Research Council (CNR), Area della Ricerca, Via Giuseppe Moruzzi 1, 56124 Pisa, Italy
| | - Elena Novelli
- Neuroscience Institute, Italian National Research Council (CNR), Area della Ricerca, Via Giuseppe Moruzzi 1, 56124 Pisa, Italy
| | - Ilaria Piano
- Department of Pharmacy, University of Pisa, Pisa, Italy
| | | | - Enrica Strettoi
- Neuroscience Institute, Italian National Research Council (CNR), Area della Ricerca, Via Giuseppe Moruzzi 1, 56124 Pisa, Italy.
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Transgenic Mice Overexpressing Serum Retinol-Binding Protein Develop Progressive Retinal Degeneration through a Retinoid-Independent Mechanism. Mol Cell Biol 2015; 35:2771-89. [PMID: 26055327 DOI: 10.1128/mcb.00181-15] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Accepted: 06/01/2015] [Indexed: 12/19/2022] Open
Abstract
Serum retinol-binding protein 4 (RBP4) is the sole specific transport protein for retinol in the blood, but it is also an adipokine with retinol-independent, proinflammatory activity associated with obesity, insulin resistance, type 2 diabetes, and cardiovascular disease. Moreover, two separate studies reported that patients with proliferative diabetic retinopathy have increased serum RBP4 levels compared to patients with mild or no retinopathy, yet the effect of increased levels of RBP4 on the retina has not been studied. Here we show that transgenic mice overexpressing RBP4 (RBP4-Tg mice) develop progressive retinal degeneration, characterized by photoreceptor ribbon synapse deficiency and subsequent bipolar cell loss. Ocular retinoid and bisretinoid levels are normal in RBP4-Tg mice, demonstrating that a retinoid-independent mechanism underlies retinal degeneration. Increased expression of pro-interleukin-18 (pro-IL-18) mRNA and activated IL-18 protein and early-onset microglia activation in the retina suggest that retinal degeneration is driven by a proinflammatory mechanism. Neither chronic systemic metabolic disease nor other retinal insults are required for RBP4 elevation to promote retinal neurodegeneration, since RBP4-Tg mice do not have coincident retinal vascular pathology, obesity, dyslipidemia, or hyperglycemia. These findings suggest that elevation of serum RBP4 levels could be a risk factor for retinal damage and vision loss in nondiabetic as well as diabetic patients.
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Aslanidis A, Karlstetter M, Scholz R, Fauser S, Neumann H, Fried C, Pietsch M, Langmann T. Activated microglia/macrophage whey acidic protein (AMWAP) inhibits NFκB signaling and induces a neuroprotective phenotype in microglia. J Neuroinflammation 2015; 12:77. [PMID: 25928566 PMCID: PMC4417279 DOI: 10.1186/s12974-015-0296-6] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Accepted: 04/07/2015] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND Microglia reactivity is a hallmark of neurodegenerative diseases. We have previously identified activated microglia/macrophage whey acidic protein (AMWAP) as a counter-regulator of pro-inflammatory response. Here, we studied its mechanisms of action with a focus on toll-like receptor (TLR) and nuclear factor κB (NFκB) signaling. METHODS Recombinant AMWAP was produced in Escherichia coli and HEK293 EBNA cells and purified by affinity chromatography. AMWAP uptake was identified by fluorescent labeling, and pro-inflammatory microglia markers were measured by qRT-PCR after stimulation with TLR ligands. NFκB pathway proteins were assessed by immunocytochemistry, Western blot, and immunoprecipitation. A 20S proteasome activity assay was used to investigate the anti-peptidase activity of AMWAP. Microglial neurotoxicity was estimated by nitrite measurement and quantification of caspase 3/7 levels in 661W photoreceptors cultured in the presence of microglia-conditioned medium. Microglial proliferation was investigated using flow cytometry, and their phagocytosis was monitored by the uptake of 661W photoreceptor debris. RESULTS AMWAP was secreted from lipopolysaccharide (LPS)-activated microglia and recombinant AMWAP reduced gene transcription of IL6, iNOS, CCL2, CASP11, and TNFα in BV-2 microglia treated with LPS as TLR4 ligand. This effect was replicated with murine embryonic stem cell-derived microglia (ESdM) and primary brain microglia. AMWAP also diminished pro-inflammatory markers in microglia activated with the TLR2 ligand zymosan but had no effects on IL6, iNOS, and CCL2 transcription in cells treated with CpG oligodeoxynucleotides as TLR9 ligand. Microglial uptake of AMWAP effectively inhibited TLR4-dependent NFκB activation by preventing IRAK-1 and IκBα proteolysis. No inhibition of IκBα phosphorylation or ubiquitination and no influence on overall 20S proteasome activity were observed. Functionally, both microglial nitric oxide (NO) secretion and 661W photoreceptor apoptosis were significantly reduced after AMWAP treatment. AMWAP promoted the filopodia formation of microglia and increased the phagocytic uptake of apoptotic 661W photoreceptor cells. CONCLUSIONS AMWAP is secreted from reactive microglia and acts in a paracrine fashion to counter-balance TLR2/TLR4-induced reactivity through NFκB inhibition. AMWAP also induces a neuroprotective microglial phenotype with reduced neurotoxicity and increased phagocytosis. We therefore hypothesize that anti-inflammatory whey acidic proteins could have a therapeutic potential in neurodegenerative diseases of the brain and the retina.
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Affiliation(s)
- Alexander Aslanidis
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, University of Cologne, Kerpener Strasse 62, D-50931, Cologne, Germany.
| | - Marcus Karlstetter
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, University of Cologne, Kerpener Strasse 62, D-50931, Cologne, Germany.
| | - Rebecca Scholz
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, University of Cologne, Kerpener Strasse 62, D-50931, Cologne, Germany.
| | - Sascha Fauser
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, University of Cologne, Kerpener Strasse 62, D-50931, Cologne, Germany.
| | - Harald Neumann
- Institute of Reconstructive Neurobiology, University of Bonn, Sigmund-Freud-Straße 25, D-53127, Bonn, Germany.
| | - Cora Fried
- Department of Pharmacology, University of Cologne, Gleueler Straße 24, D-50931, Cologne, Germany.
| | - Markus Pietsch
- Department of Pharmacology, University of Cologne, Gleueler Straße 24, D-50931, Cologne, Germany.
| | - Thomas Langmann
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, University of Cologne, Kerpener Strasse 62, D-50931, Cologne, Germany.
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Syeda S, Patel AK, Lee T, Hackam AS. Reduced photoreceptor death and improved retinal function during retinal degeneration in mice lacking innate immunity adaptor protein MyD88. Exp Neurol 2015; 267:1-12. [PMID: 25725353 DOI: 10.1016/j.expneurol.2015.02.027] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Revised: 01/21/2015] [Accepted: 02/18/2015] [Indexed: 12/20/2022]
Abstract
The injury inflammatory response mediated by the innate immune system is an important contributor to neurodegeneration in the central nervous system (CNS) and retina. A major branch of the innate immune system is regulated by the Toll-like receptors (TLRs), which are receptors for endogenous damage associated molecules released from injured cells as well as pathogen-derived molecules, and interleukin-1 receptors (IL-1R), which are activated by IL-1α, IL-1β and IL-18 cytokines. TLRs and IL-1R are expressed on immune and non-immune cell types and act as first responders to cell damage, which results in tissue repair, or inflammation and apoptosis. Both TLR and IL-1R require the adaptor protein myeloid differentiation primary response gene 88 (MyD88) for signaling. Although inflammation is implicated in neuronal death in the retina, the role of MyD88-dependent TLR and IL-1R signaling in retinal degeneration is unknown. Therefore, the purpose of this study was to investigate the role of MyD88-mediated signaling in neuronal degeneration in the retinal degeneration 1 (rd1) mouse model, which exhibits a phenotype of rapid photoreceptor death and inflammation. To generate rd1 mice lacking the MyD88 gene, rd1 were bred with MyD88 knockout mice (MyD88(-/-)) for several generations to produce rd1/MyD88(+/+) and rd1/MyD88(-/-) genotypes. Chemokine mRNA expression levels were analyzed by qRT-PCR, and recruitment of activated microglia was quantified by immunodetection of the IBA-1 protein. Retinal outer nuclear layer cell counts were performed to quantify photoreceptor degeneration, and retinal function was assessed using electroretinograms (ERG). Our results revealed that retinal expression of Ccl2, Ccl4, Ccl7 and Cxcl10 was reduced by 2 to 8-fold in rd1/MyD88(-/-) mice compared with rd1/MyD88(+/+) mice (p<0.05), which coincided with attenuated microglial activation, higher numbers of photoreceptors and higher retina responses to photopic and scotopic stimuli. At later ages, rd1/MyD88(-/-) had reduced chemokine expression and higher photopic responses but no change in microglial recruitment compared with rd1 mice with functional MyD88. In conclusion, lack of MyD88-mediated signaling increased photoreceptor survival and retina function in rd1 mice, which implicates MyD88-mediated innate immunity pathways as an important pathogenic factor during retinal degeneration.
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Affiliation(s)
- Sarah Syeda
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, McKnight Bldg., Rm. 407, 1638 NW 10th Ave., Miami, FL 33136, USA
| | - Amit K Patel
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, McKnight Bldg., Rm. 407, 1638 NW 10th Ave., Miami, FL 33136, USA
| | - Tinthu Lee
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, McKnight Bldg., Rm. 407, 1638 NW 10th Ave., Miami, FL 33136, USA
| | - Abigail S Hackam
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, McKnight Bldg., Rm. 407, 1638 NW 10th Ave., Miami, FL 33136, USA.
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Kevany BM, Zhang N, Jastrzebska B, Palczewski K. Animals deficient in C2Orf71, an autosomal recessive retinitis pigmentosa-associated locus, develop severe early-onset retinal degeneration. Hum Mol Genet 2015; 24:2627-40. [PMID: 25616964 DOI: 10.1093/hmg/ddv025] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Accepted: 01/21/2015] [Indexed: 02/01/2023] Open
Abstract
Genetic mapping was recently used to identify the underlying cause for a previously uncharacterized cohort of autosomal recessive retinitis pigmentosa cases. Genetic mapping of affected individuals resulted in the identification of an uncharacterized gene, C2Orf71, as the causative locus. However, initial homology searches failed to reveal similarities to any previously characterized protein or domain. To address this issue, we characterized the mouse homolog, BC027072. Immunohistochemistry with a custom polyclonal antibody showed staining localized to the inner segments (IS) of photoreceptor cells, as well as the outer segments (OS) of cone cells. A knockout mouse line (BC(-/-)) was generated and demonstrated that loss of this gene results in a severe, early-onset retinal degeneration. Histology and electron microscopy (EM) revealed disorganized OS as early as 3 weeks with complete loss by 24 weeks of age. EM micrographs displayed packets of cellular material containing OS discs or IS organelles in the OS region and abnormal retinal pigmented epithelium cells. Analyses of retinoids and rhodopsin levels showed <20% in BC(-/-) versus wild-type mice early in development. Electroretinograms demonstrated that affected mice were virtually non-responsive to light by 8 weeks of age. Lastly, RNAseq analysis of ocular gene expression in BC(-/-) mice revealed clues to the causes of the progressive retinal degenerations. Although its function remains unknown, this protein appears essential for normal OS development/maintenance and vision in humans and mice. RNAseq data are available in the GEO database under accession: GSE63810.
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Affiliation(s)
- Brian M Kevany
- Department of Pharmacology, Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Ning Zhang
- Department of Pharmacology, Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Beata Jastrzebska
- Department of Pharmacology, Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Krzysztof Palczewski
- Department of Pharmacology, Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA
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Marquioni-Ramella MD, Suburo AM. Photo-damage, photo-protection and age-related macular degeneration. Photochem Photobiol Sci 2015. [DOI: 10.1039/c5pp00188a] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The course of Age-related Macular Degeneration (AMD) is described as the effect of light (400–580 nm) on various molecular targets in photoreceptors and the retinal pigment epithelium (RPE). Photo-damage is followed by inflammation, increasing oxidative stress and, probably, unveiling new photosensitive molecules.
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Affiliation(s)
| | - Angela M. Suburo
- Medicina Celular y Molecular
- Facultad de Ciencias Biomédicas
- Universidad Austral
- Pilar B1629AHJ
- Argentina
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134
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Karlstetter M, Scholz R, Rutar M, Wong WT, Provis JM, Langmann T. Retinal microglia: just bystander or target for therapy? Prog Retin Eye Res 2014; 45:30-57. [PMID: 25476242 DOI: 10.1016/j.preteyeres.2014.11.004] [Citation(s) in RCA: 374] [Impact Index Per Article: 37.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Revised: 11/20/2014] [Accepted: 11/25/2014] [Indexed: 10/24/2022]
Abstract
Resident microglial cells can be regarded as the immunological watchdogs of the brain and the retina. They are active sensors of their neuronal microenvironment and rapidly respond to various insults with a morphological and functional transformation into reactive phagocytes. There is strong evidence from animal models and in situ analyses of human tissue that microglial reactivity is a common hallmark of various retinal degenerative and inflammatory diseases. These include rare hereditary retinopathies such as retinitis pigmentosa and X-linked juvenile retinoschisis but also comprise more common multifactorial retinal diseases such as age-related macular degeneration, diabetic retinopathy, glaucoma, and uveitis as well as neurological disorders with ocular manifestation. In this review, we describe how microglial function is kept in balance under normal conditions by cross-talk with other retinal cells and summarize how microglia respond to different forms of retinal injury. In addition, we present the concept that microglia play a key role in local regulation of complement in the retina and specify aspects of microglial aging relevant for chronic inflammatory processes in the retina. We conclude that this resident immune cell of the retina cannot be simply regarded as bystander of disease but may instead be a potential therapeutic target to be modulated in the treatment of degenerative and inflammatory diseases of the retina.
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Affiliation(s)
- Marcus Karlstetter
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, University of Cologne, Cologne, Germany
| | - Rebecca Scholz
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, University of Cologne, Cologne, Germany
| | - Matt Rutar
- The John Curtin School of Medical Research, The Australian National University (ANU), Canberra, Australian Capital Territory, Australia
| | - Wai T Wong
- Unit on Neuron-Glia Interactions in Retinal Disease, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Jan M Provis
- The John Curtin School of Medical Research, The Australian National University (ANU), Canberra, Australian Capital Territory, Australia
| | - Thomas Langmann
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, University of Cologne, Cologne, Germany.
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135
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A profile of transcriptomic changes in the rd10 mouse model of retinitis pigmentosa. Mol Vis 2014; 20:1612-28. [PMID: 25489233 PMCID: PMC4235044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Accepted: 11/12/2014] [Indexed: 11/16/2022] Open
Abstract
PURPOSE Retinitis pigmentosa (RP) is a photoreceptor disease that affects approximately 100,000 people in the United States. Treatment options are limited, and the prognosis for most patients is progressive vision loss. Unfortunately, understanding of the molecular underpinnings of RP initiation and progression is still limited. However, the development of animal models of RP, coupled with high-throughput sequencing, has provided an opportunity to study the underlying cellular and molecular changes in this disease. METHODS Using RNA-Seq, we present the first retinal transcriptome analysis of the rd10 murine model of retinal degeneration. RESULTS Our data confirm the loss of rod-specific transcripts and the increased relative expression of Müller-specific transcripts, emphasizing the important role of reactive gliosis and innate immune activation in RP. Moreover, we report substantial changes in relative isoform usage among neuronal differentiation and morphogenesis genes, including a marked shift to shorter transcripts. CONCLUSIONS Our analyses implicate remodeling of the inner retina and possible Müller cell dedifferentiation.
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136
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Toll-like receptor 4 in bone marrow-derived cells contributes to the progression of diabetic retinopathy. Mediators Inflamm 2014; 2014:858763. [PMID: 25214718 PMCID: PMC4156976 DOI: 10.1155/2014/858763] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2014] [Revised: 06/25/2014] [Accepted: 07/24/2014] [Indexed: 01/24/2023] Open
Abstract
Diabetic retinopathy (DR) is a major microvascular complication in diabetics, and its mechanism is not fully understood. Toll-like receptor 4 (TLR4) plays a pivotal role in the maintenance of the inflammatory state during DR, and the deletion of TLR4 eventually alleviates the diabetic inflammatory state. To further elucidate the mechanism of DR, we used bone marrow transplantation to establish reciprocal chimeric animals of TLR4 mutant mice and TLR4 WT mice combined with diabetes mellitus (DM) induction by streptozotocin (STZ) treatment to identify the role of TLR4 in different cell types in the development of the proinflammatory state during DR. TLR4 mutation did not block the occurrence of high blood glucose after STZ injection compared with WT mice but did alleviate the progression of DR and alter the expression of the small vessel proliferation-related genes, vascular endothelial growth factor (VEGF), and hypoxia inducible factor-1α (HIF-1α). Grafting bone marrow-derived cells from TLR4 WT mice into TLR4 mutant mice increased the levels of TNF-α, IL-1β, and MIP-2 and increased the damage to the retina. Similarly, VEGF and HIF-1α expression were restored by the bone marrow transplantation. These findings identify an essential role for TLR4 in bone marrow-derived cells contributing to the progression of DR.
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137
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Suppression of microglial activation is neuroprotective in a mouse model of human retinitis pigmentosa. J Neurosci 2014; 34:8139-50. [PMID: 24920619 DOI: 10.1523/jneurosci.5200-13.2014] [Citation(s) in RCA: 177] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Retinitis pigmentosa (RP) is a photoreceptor-degenerative disease caused by various mutations and is characterized by death of rod photoreceptor cell followed by gradual death of cone photoreceptors. The molecular mechanisms that lead to rod and cone death are not yet fully understood. Neuroinflammation contributes to the progression of many chronic neurodegenerative disorders. However, it remains to be determined how microglia contribute to photoreceptor disruption in RP. In this study, we explored the role of microglia as a contributor to photoreceptor degeneration in the rd10 mouse model of RP. First, we demonstrated that microglia activation was an early alteration in RP retinas. Inhibition of microglia activation by minocycline reduced photoreceptor apoptosis and significantly improved retinal structure and function and visual behavior in rd10 mice. Second, we identified that minocycline exerted its neuroprotective effects through both anti-inflammatory and anti-apoptotic mechanisms. Third, we found that Cx3cr1 deficiency dysregulated microglia activation and subsequently resulted in increased photoreceptor vulnerability in rd10 mice, suggesting that the Cx3cl1/Cx3cr1 signaling pathway might protect against microglia neurotoxicity. We concluded that suppression of neuroinflammatory responses could be a potential treatment strategy aimed at improving photoreceptor survival in human RP.
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138
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Cuenca N, Fernández-Sánchez L, Campello L, Maneu V, De la Villa P, Lax P, Pinilla I. Cellular responses following retinal injuries and therapeutic approaches for neurodegenerative diseases. Prog Retin Eye Res 2014; 43:17-75. [PMID: 25038518 DOI: 10.1016/j.preteyeres.2014.07.001] [Citation(s) in RCA: 296] [Impact Index Per Article: 29.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Revised: 07/03/2014] [Accepted: 07/07/2014] [Indexed: 01/17/2023]
Abstract
Retinal neurodegenerative diseases like age-related macular degeneration, glaucoma, diabetic retinopathy and retinitis pigmentosa each have a different etiology and pathogenesis. However, at the cellular and molecular level, the response to retinal injury is similar in all of them, and results in morphological and functional impairment of retinal cells. This retinal degeneration may be triggered by gene defects, increased intraocular pressure, high levels of blood glucose, other types of stress or aging, but they all frequently induce a set of cell signals that lead to well-established and similar morphological and functional changes, including controlled cell death and retinal remodeling. Interestingly, an inflammatory response, oxidative stress and activation of apoptotic pathways are common features in all these diseases. Furthermore, it is important to note the relevant role of glial cells, including astrocytes, Müller cells and microglia, because their response to injury is decisive for maintaining the health of the retina or its degeneration. Several therapeutic approaches have been developed to preserve retinal function or restore eyesight in pathological conditions. In this context, neuroprotective compounds, gene therapy, cell transplantation or artificial devices should be applied at the appropriate stage of retinal degeneration to obtain successful results. This review provides an overview of the common and distinctive features of retinal neurodegenerative diseases, including the molecular, anatomical and functional changes caused by the cellular response to damage, in order to establish appropriate treatments for these pathologies.
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Affiliation(s)
- Nicolás Cuenca
- Department of Physiology, Genetics and Microbiology, University of Alicante, Alicante, Spain; Multidisciplinary Institute for Environmental Studies "Ramon Margalef", University of Alicante, Alicante, Spain.
| | - Laura Fernández-Sánchez
- Department of Physiology, Genetics and Microbiology, University of Alicante, Alicante, Spain
| | - Laura Campello
- Department of Physiology, Genetics and Microbiology, University of Alicante, Alicante, Spain
| | - Victoria Maneu
- Department of Optics, Pharmacology and Anatomy, University of Alicante, Alicante, Spain
| | - Pedro De la Villa
- Department of Systems Biology, University of Alcalá, Alcalá de Henares, Spain
| | - Pedro Lax
- Department of Physiology, Genetics and Microbiology, University of Alicante, Alicante, Spain
| | - Isabel Pinilla
- Department of Ophthalmology, Lozano Blesa University Hospital, Aragon Institute of Health Sciences, Zaragoza, Spain
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139
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Hussein KA, Choksi K, Akeel S, Ahmad S, Megyerdi S, El-Sherbiny M, Nawaz M, Abu El-Asrar A, Al-Shabrawey M. Bone morphogenetic protein 2: a potential new player in the pathogenesis of diabetic retinopathy. Exp Eye Res 2014; 125:79-88. [PMID: 24910902 DOI: 10.1016/j.exer.2014.05.012] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Revised: 03/10/2014] [Accepted: 05/15/2014] [Indexed: 12/23/2022]
Abstract
Diabetic retinopathy (DR) is one of the most common complications of diabetes mellitus. Vision loss in DR principally occurs due to breakdown of the blood-retinal barrier (BRB), leading to macular edema, retinal detachment and inner retinal and vitreous hemorrhage. Several growth factors have been shown to play crucial role in the development of these vascular changes; however, the cellular and molecular mechanisms of DR are not yet fully revealed. In the current study we investigated the role of bone morphogenetic protein-2 (BMP2) in DR. We examined the changes in the protein levels of BMP2 in human vitreous and retina in addition to the mouse retina of streptozotocin-induced diabetes. To detect the source of BMP2 during diabetes, human retinal endothelial cells (hRECs) were subjected to high glucose (HG) for 5 days and levels of BMP2 protein were analyzed in conditioned media of these cells relative to control. We also evaluated the effect of BMP2 on the levels of VEGF in cultured rat Müller cells (rMC1). In addition, we tested the pro-inflammatory effects of BMP2 by examining its effect on leukocyte adhesion to cultured hRECs, and levels of adhesion molecules and cytokines production. Finally, the effect of different concentrations of BMP2 on permeability of confluent monolayer of hRECs was evaluated using FITC-Dextran flux permeability assay and by measuring Transcellular Electrical Resistance (TER) using Electric Cell-substrate Impedance Sensing (ECIS). Our results show, for the first time, the up-regulation of BMP2 in diabetic human and mouse retinas in addition to its detection in vitreous of patients with proliferative DR (72 ± 7 pg/ml). In vitro, hRECs showed upregulation of BMP2 in HG conditions suggesting that these cells are a potential source of BMP2 in diabetic conditions. Furthermore, BMP2 induced VEGF secretion by Müller cells in-vitro; and showed a dose response in increasing permeability of cultured hRECs. Meanwhile, BMP2 pro-inflammatory effects were recognized by its ability to induce leukocyte adhesion to the hRECs, intercellular adhesion molecule-1 (ICAM-1) and upregulation of interleukin-6 and 8 (IL-6 and IL-8). These results show that BMP2 could be a contributing growth factor to the development of microvascular dysfunction during DR via enhancing both pro-angiogenic and inflammatory pathways. Our findings suggest BMP2 as a potential therapeutic target to prevent/treat DR.
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Affiliation(s)
- Khaled A Hussein
- Department of Oral Biology/Anatomy College of Dental Medicine, Georgia Reagents University (Augusta) (GRU(A)), USA; Vision Discovery Institute, Medical College of Georgia, GRU(A), USA; Oral and Dental Research Division, Department of Surgery and Medicine, National Research Center, Egypt
| | - Karishma Choksi
- Department of Oral Biology/Anatomy College of Dental Medicine, Georgia Reagents University (Augusta) (GRU(A)), USA; Vision Discovery Institute, Medical College of Georgia, GRU(A), USA
| | - Sara Akeel
- Department of Oral Biology/Anatomy College of Dental Medicine, Georgia Reagents University (Augusta) (GRU(A)), USA
| | - Saif Ahmad
- Vision Discovery Institute, Medical College of Georgia, GRU(A), USA; Department of Biological Sciences, Rabigh College of Science and Arts, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Sylvia Megyerdi
- Department of Oral Biology/Anatomy College of Dental Medicine, Georgia Reagents University (Augusta) (GRU(A)), USA
| | - Mohamed El-Sherbiny
- Department of Oral Biology/Anatomy College of Dental Medicine, Georgia Reagents University (Augusta) (GRU(A)), USA; Vision Discovery Institute, Medical College of Georgia, GRU(A), USA; Department of Anatomy, Mansoura Faculty of Medicine, Mansoura, Egypt
| | - Mohamed Nawaz
- Department of Ophthalmology, King Saud University, Riyadh, Saudi Arabia
| | | | - Mohamed Al-Shabrawey
- Department of Oral Biology/Anatomy College of Dental Medicine, Georgia Reagents University (Augusta) (GRU(A)), USA; Vision Discovery Institute, Medical College of Georgia, GRU(A), USA; Department of Anatomy, Mansoura Faculty of Medicine, Mansoura, Egypt; Department of Ophthalmology, Medical College of Georgia, GRU(A), USA; Department of Cellular Biology and Anatomy, GRU(A), USA.
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140
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Retinal metabolism in humans induces the formation of an unprecedented lipofuscin fluorophore ‘pdA2E’. Biochem J 2014; 460:343-52. [PMID: 24712709 DOI: 10.1042/bj20140089] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
We identified a novel by-product of retinal metabolism called pdA2E in the lipofuscin of the retinal pigment epithelium, demonstrated the photoisomerization and oxidation of pdA2E, and proposed a non-enzymatic mechanism for its formation in the retina.
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141
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Two-photon microscopy reveals early rod photoreceptor cell damage in light-exposed mutant mice. Proc Natl Acad Sci U S A 2014; 111:E1428-37. [PMID: 24706832 DOI: 10.1073/pnas.1317986111] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Atrophic age-related and juvenile macular degeneration are especially devastating due to lack of an effective cure. Two retinal cell types, photoreceptor cells and the adjacent retinal pigmented epithelium (RPE), reportedly display the earliest pathological changes. Abca4(-/-)Rdh8(-/-) mice, which mimic many features of human retinal degeneration, allowed us to determine the sequence of light-induced events leading to retinal degeneration. Using two-photon microscopy with 3D reconstruction methodology, we observed an initial strong retinoid-derived fluorescence and expansion of Abca4(-/-)Rdh8(-/-) mouse rod cell outer segments accompanied by macrophage infiltration after brief exposure of the retina to bright light. Additionally, light-dependent fluorescent compounds produced in rod outer segments were not transferred to the RPE of mice genetically defective in RPE phagocytosis. Collectively, these findings suggest that for light-induced retinopathies in mice, rod photoreceptors are the primary site of toxic retinoid accumulation and degeneration, followed by secondary changes in the RPE.
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142
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Kohno H, Maeda T, Perusek L, Pearlman E, Maeda A. CCL3 production by microglial cells modulates disease severity in murine models of retinal degeneration. THE JOURNAL OF IMMUNOLOGY 2014; 192:3816-27. [PMID: 24639355 DOI: 10.4049/jimmunol.1301738] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Many degenerative retinal diseases illustrate retinal inflammatory changes that include infiltration of microglia and macrophages into the subretinal space. In this study, we examined the role of chemokines in the Abca4(-/-)Rdh8(-/-) mouse model of Stargardt disease and the Mertk(-/-) mouse model of retinitis pigmentosa. PCR array analysis of 84 chemokines and related molecules revealed 84.6-fold elevated expression of Ccl3 (MIP-1a) 24 h after light exposure in Abca4(-/-)Rdh8(-/-) mice. Only MIP-1 chemokines, including Ccl3 and Ccl4, displayed peak expression 24 h after light exposure, and peaked earlier than the other chemokines. Secretion of Ccl3 was documented only in microglia, whereas both microglia and retinal pigment epithelium cells produced Ccl2. Exposure of Cx3Cr1(gfp/Δ)Abca4(-/-)Rdh8(-/-) mice to intense light resulted in the appearance of Cx3Cr1GFP(+) monocytes in the subretinal space. To address the in vivo role of CCL3 in retinal degeneration, Ccl3(-/-)Abca4(-/-)Rdh8(-/-) mice and Ccl3(-/-)Mertk(-/-) mice were generated. Following intense light exposure, Ccl3(-/-)Abca4(-/-)Rdh8(-/-) mice displayed persistent retinal inflammation with appearance of Iba-1(+) cells in the subretinal space, severe photoreceptor cell death, and increased Ccl4 expression compared with Abca4(-/-)Rdh8(-/-) mice. In contrast, Ccl3(-/-)Abca4(-/-)Rdh8(-/-) mice exhibited a milder retinal inflammation and degeneration than Abca4(-/-)Rdh8(-/-) mice did in age-related chronic retinal degeneration under room light conditions. The deficiency of Ccl3 also attenuated the severity of retinal degeneration in Mertk(-/-) mice. Taken together, our results indicate that Ccl3 has an essential role in regulating the severity of retinal inflammation and degeneration in these mouse models.
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Affiliation(s)
- Hideo Kohno
- Department of Pharmacology, Case Western Reserve University, Cleveland, OH 44106
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143
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Correlation of cytokine levels and microglial cell infiltration during retinal degeneration in RCS rats. PLoS One 2013; 8:e82061. [PMID: 24349184 PMCID: PMC3862575 DOI: 10.1371/journal.pone.0082061] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Accepted: 10/17/2013] [Indexed: 01/09/2023] Open
Abstract
Microglial cells, which are immunocompetent cells, are involved in all diseases of the central nervous system. During their activation in various diseases, a variety of soluble factors are released. In the present study, the correlation between cytokine levels and microglial cell migration in the course of retinal degeneration of Royal College of Surgeons (RCS) rats was evaluated. MFG-E8 and CD11b were used to confirm the microglial cells. In the retina of RCS rats, the mRNA expression of seven genes (MFG-E8 and its integrins αυ and ß5, CD11b and the cytokines TNF-α, IL-1ß, and MCP-1) formed almost similar bimodal peak distributions, which were centred at P7 and P45 to P60. In contrast, in rdy rats, which comprised the control group, a unimodal peak distribution centred at P14 was observed. The gene expression accompanied the activation and migration of microglial cells from the inner to the outer layer of the retina during the process of degeneration. Principal component analysis and discriminant function analysis revealed that the expression of these seven genes, especially TNF-α and CD11b, positively correlated with retinal degeneration and microglial activity during retinal degeneration in RCS rats, but not in the control rats. Furthermore, linear regression analysis demonstrated a significant correlation between the expression of these genes and the activation of microglial cells in the dystrophic retina. Our findings suggest that the suppression of microglial cells and the blockade of their cytotoxic effects may constitute a novel therapeutic strategy for treating photoreceptor death in various retinal disorders.
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144
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Chen Y, Palczewska G, Mustafi D, Golczak M, Dong Z, Sawada O, Maeda T, Maeda A, Palczewski K. Systems pharmacology identifies drug targets for Stargardt disease-associated retinal degeneration. J Clin Invest 2013; 123:5119-34. [PMID: 24231350 DOI: 10.1172/jci69076] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2013] [Accepted: 09/12/2013] [Indexed: 12/22/2022] Open
Abstract
A systems pharmacological approach that capitalizes on the characterization of intracellular signaling networks can transform our understanding of human diseases and lead to therapy development. Here, we applied this strategy to identify pharmacological targets for the treatment of Stargardt disease, a severe juvenile form of macular degeneration. Diverse GPCRs have previously been implicated in neuronal cell survival, and crosstalk between GPCR signaling pathways represents an unexplored avenue for pharmacological intervention. We focused on this receptor family for potential therapeutic interventions in macular disease. Complete transcriptomes of mouse and human samples were analyzed to assess the expression of GPCRs in the retina. Focusing on adrenergic (AR) and serotonin (5-HT) receptors, we found that adrenoceptor α 2C (Adra2c) and serotonin receptor 2a (Htr2a) were the most highly expressed. Using a mouse model of Stargardt disease, we found that pharmacological interventions that targeted both GPCR signaling pathways and adenylate cyclases (ACs) improved photoreceptor cell survival, preserved photoreceptor function, and attenuated the accumulation of pathological fluorescent deposits in the retina. These findings demonstrate a strategy for the identification of new drug candidates and FDA-approved drugs for the treatment of monogenic and complex diseases.
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MESH Headings
- ATP-Binding Cassette Transporters/deficiency
- ATP-Binding Cassette Transporters/genetics
- Adenine/analogs & derivatives
- Adenine/pharmacology
- Adenine/therapeutic use
- Adenylyl Cyclase Inhibitors
- Adrenergic alpha-Agonists/pharmacology
- Adrenergic alpha-Agonists/therapeutic use
- Adrenergic alpha-Antagonists/pharmacology
- Adrenergic alpha-Antagonists/therapeutic use
- Alcohol Oxidoreductases/deficiency
- Alcohol Oxidoreductases/genetics
- Animals
- Cell Survival
- Disease Models, Animal
- Doxazosin/pharmacology
- Doxazosin/therapeutic use
- Drug Evaluation, Preclinical
- Guanabenz/pharmacology
- Guanabenz/therapeutic use
- Humans
- Light/adverse effects
- Macaca fascicularis
- Macular Degeneration/congenital
- Macular Degeneration/drug therapy
- Macular Degeneration/genetics
- Macular Degeneration/prevention & control
- Mice
- Mice, Inbred BALB C
- Mice, Knockout
- Molecular Targeted Therapy
- Nerve Tissue Proteins/biosynthesis
- Nerve Tissue Proteins/genetics
- Photoreceptor Cells, Vertebrate/drug effects
- Photoreceptor Cells, Vertebrate/pathology
- Photoreceptor Cells, Vertebrate/physiology
- Photoreceptor Cells, Vertebrate/radiation effects
- Reactive Oxygen Species
- Receptor, Serotonin, 5-HT2A/biosynthesis
- Receptor, Serotonin, 5-HT2A/genetics
- Receptors, Adrenergic, alpha-2/biosynthesis
- Receptors, Adrenergic, alpha-2/genetics
- Receptors, G-Protein-Coupled/biosynthesis
- Receptors, G-Protein-Coupled/genetics
- Serotonin Antagonists/pharmacology
- Serotonin Antagonists/therapeutic use
- Signal Transduction
- Stargardt Disease
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145
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Li J, Yao K, Yu X, Dong X, Gan L, Luo C, Wu Y. Identification of a novel lipofuscin pigment (iisoA2E) in retina and its effects in the retinal pigment epithelial cells. J Biol Chem 2013; 288:35671-82. [PMID: 24169698 DOI: 10.1074/jbc.m113.511386] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Lipofuscin accumulation in retinal pigment epithelial (RPE) cells of the eye implicates the etiologies of Stargardt disease and age-related macular degeneration, a leading cause of blindness in the elderly. Here, we have identified a previously unknown RPE lipofuscin component. By one- and two-dimensional NMR techniques and mass spectrometry, we confirmed that this compound is a new type of pyridinium bisretinoid presenting an unusual structure, in which two polyenic side chains are attached to adjacent carbons of a pyridinium ring. This pigment is a light-induced isomer of isoA2E, rather than A2E, referred to as iisoA2E. This pigment is a fluorescent lipofuscin compound with absorbance maxima at ∼430 and 352 nm detected in human, pig, mouse, and bovine eyes. Formation of iisoA2E was found in reaction mixtures of all-trans-retinal and ethanolamine. Excess intracellular accumulation of this adduct in RPE cells in vitro leads to a significant loss of cell viability and caused membrane damage. Phospholipase D-mediated phosphodiester cleavage of the A2PE series generated isoA2E and iisoA2E, in addition to A2E, thus corroborating the presence of isoA2PE and iisoA2PE that may serve as biosynthetic precursors of isoA2E and iisoA2E.
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Affiliation(s)
- Jie Li
- From the College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China and
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146
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Sennlaub F, Auvynet C, Calippe B, Lavalette S, Poupel L, Hu SJ, Dominguez E, Camelo S, Levy O, Guyon E, Saederup N, Charo IF, Rooijen NV, Nandrot E, Bourges JL, Behar-Cohen F, Sahel JA, Guillonneau X, Raoul W, Combadiere C. CCR2(+) monocytes infiltrate atrophic lesions in age-related macular disease and mediate photoreceptor degeneration in experimental subretinal inflammation in Cx3cr1 deficient mice. EMBO Mol Med 2013; 5:1775-93. [PMID: 24142887 PMCID: PMC3840491 DOI: 10.1002/emmm.201302692] [Citation(s) in RCA: 214] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Revised: 08/28/2013] [Accepted: 08/30/2013] [Indexed: 12/11/2022] Open
Abstract
Atrophic age-related macular degeneration (AMD) is associated with the subretinal accumulation of mononuclear phagocytes (MPs). Their role in promoting or inhibiting retinal degeneration is unknown. We here show that atrophic AMD is associated with increased intraocular CCL2 levels and subretinal CCR2+ inflammatory monocyte infiltration in patients. Using age- and light-induced subretinal inflammation and photoreceptor degeneration in Cx3cr1 knockout mice, we show that subretinal Cx3cr1 deficient MPs overexpress CCL2 and that both the genetic deletion of CCL2 or CCR2 and the pharmacological inhibition of CCR2 prevent inflammatory monocyte recruitment, MP accumulation and photoreceptor degeneration in vivo. Our study shows that contrary to CCR2 and CCL2, CX3CR1 is constitutively expressed in the retina where it represses the expression of CCL2 and the recruitment of neurotoxic inflammatory CCR2+ monocytes. CCL2/CCR2 inhibition might represent a powerful tool for controlling inflammation and neurodegeneration in AMD.
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Affiliation(s)
- Florian Sennlaub
- Inserm, U 968, Paris, France; UPMC Univ Paris 06, UMR_S 968, Institut de la Vision, Paris, France; Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, INSERM-DHOS CIC 503, Paris, France; Hôtel Dieu, Service d'Ophtalmologie, Centre de Recherche Ophtalmologique, Paris, France
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